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Identification of Rüppell´s Vulture and African White-backed Vulture and Vagrancy in the WP

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Identification of Rüppell´s Vulture and African White-backed Vulture and Vagrancy in the WP

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349
[Dutch Birding 38: 349-375, 2016]
In the past, the identication of Gyps vultures in
Europe has traditionally been considered
straightforward, since Griffon Vulture G fulvus
was the only recorded member of this genus. This
changed with the rather recent addition of two
African species to the European list: Rüppell’s
Vulture G rueppelli (in 1992) and, more recently,
White-backed Vulture G africanus (in 2008), both
recorded for the rst time in Spain. Rüppell’s is
now a scarce but fairly regular visitor to the Iberian
Peninsula and beyond. To date, White-backed has
been recorded six times in the WP (Morocco,
Portugal and four in Spain) but other occurrences
may have been overlooked. Both species are quite
distinctive in adult plumage but separating juve-
nile and immature individuals can be more chal-
lenging. This is mostly due to the incomplete treat-
ment in the identication literature of individual
age-related variation, which until recently has not
been comprehensively described for the three
species (cf Forsman 2016).
This paper deals with the identication of
Rüppell’s Vulture and White-backed Vulture in a
European context and we include Griffon Vulture
to complete the picture. We particularly focus on
the individual variation of immature plumages,
Identication of Rüppell’s Vulture and
White-backed Vulture and vagrancy
in the WP
Guillermo Rodríguez & Javier Elorriaga
552 Rüppell’s Vulture / Rüppells Gier Gyps rueppelli (left) and Griffon Vulture / Vale Gier G fulvus (centre), Cadiz,
Spain, September 2014 (Yeray Seminario/Birding The Strait). This image shows an immature Rüppell’s, an adult
Griffon and a strikingly small vulture at right that at rst glance appears to be a juvenile White-backed Vulture
G africanus (with uniformly brown plumage). These three Gyps species are the focus of this paper. However, is the
right-hand bird actually a White-backed? More about this tricky identication in plate 576.
350
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
which correspond with the most frequent age
classes found among the vagrants in the WP. Our
eld experience with Rüppell’s and White-backed
comes from vagrants of West African origin at the
Strait of Gibraltar, complemented with observa-
tions during different trips to Ethiopia and Senegal.
The paper has to be used with care in the east of
the Western Palearctic (WP) region, where a dif-
ferent subspecies of Rüppell’s has reached Israel
as a vagrant from East Africa, and where Himalayan
Vulture G himalayensis and White-rumped Vulture
G bengalensis occurred as vagrant in the Arabian
peninsula. However, most features described here
can be applied in the eastern WP as well and a
brief discussion on this is offered in the last sec-
tion.
Given the alarming decline that vulture popula-
tions are experiencing throughout the African
continent (both Rüppell’s Vulture and White-
backed Vulture have been upgraded from a con-
servation status of ‘Lower Risk/Least Concern’ in
2000 to ‘Critically Endangered’ since 2012;
BirdLife International 2015), a correct assessment
of the identication criteria for hard-to-identify
immature plumages is of importance not only
within the WP boundaries but also for monitoring
populations within the regular ranges in Africa.
Distribution and geographical variation
Both Rüppell’s Vulture and White-backed Vulture
have an Afrotropical distribution, occupying a
broad belt from the southern Sahara through the
Sahel region, from Senegal to Ethiopia and
Somalia, and extending south to Kenya and north-
ern Uganda (Ferguson-Lees & Christie 2001).
White-backed also occupies an apparently dis-
junct region in southern Africa. Rüppell’s is gener-
ally associated with more arid and open land-
scapes, being regular in extremely arid desert
areas of the Sahara, whereas White-backed is
found in more wooded areas (Wacher et al 2012).
Most likely as a consequence of this habitat selec-
tion, the breeding range of Rüppell’s in West Africa
extends north into southern Mauritania, whereas
White-backed is restricted to the southern half of
Senegal (Borrow & Demey 2001, Ferguson-Lees &
Christie 2001).
Two subspecies of Rüppell’s Vulture are cur-
553 Rüppell’s Vulture / Rüppells Gier Gyps rueppelli, juvenile, Gibraltar, 25 June 2016 (Stewart Finlayson). Note
streaked plumage and relatively dark overall coloration. 554 Rüppell’s Vulture / Rüppells Gier Gyps rueppelli, second
plumage, Tarifa, Spain, 10 September 2012 (Yeray Seminario/Birding The Strait). Immatures are more chocolate
brown than juveniles. Note block of four fresh inner primaries (p5 is growing), absence of moult in secondaries and
new central pair of tail-feathers. Body patterning spotted rather than streaked.
351
rently recognised: nominate G r rueppelli occurs
across most of the species distribution area while
Abyssinian Rüppell’s Vulture G r erlangeri (hereaf-
ter erlangeri) is restricted to the Abyssinian region
(northern Ethiopia, Eritrea and Somalia) (Gill &
Donsker 2016). It is remarkable, however, that
signicant phenotypic variation is also found
within the nominate’s range; eastern birds are
paler and much more densely patterned than
those found in West Africa, especially adults (pers
obs). No geographic variation has been described
for White-backed Vulture since its split from
White-rumped Vulture G bengalensis (also named
Indian White-backed Vulture) and it is considered
monotypic. Griffon Vulture has two recognised
subspecies: G f fulvus (occupying the entire WP
range, and thus the taxon of interest in this paper)
and G f fulvescens, of which the range extends
from Afghanistan to India (Gill & Donsker 2016).
Vagrancy
African vultures, particularly White-backed
Vulture, are often found in captivity in Europe,
and proven escaped individuals have been docu-
mented, eg, adult White-backed Vultures in
Britain, Portugal and Spain and adult Rüppell’s
Vultures in, eg, Britain, Greece and the Netherlands
(April 2004) (Small 2007; Enno Ebels in litt).
Consequently, it is necessary to ensure that any
given record in the region relates to a bird not
showing signs of a history in captivity, especially
when phenology and state of moult state do not t
the pattern shown by genuine vagrants from the
Strait of Gibraltar.
Rüppell’s Vulture
The presence of Rüppell’s Vulture in Europe was
discovered in the early 1990s, when several
records occurred in southern Spain, and its occur-
rence north of the Sahara was considered rare and
irregular until the mid-2000s (Gutiérrez 2003,
Forsman 2005). Over the last decade, the number
of records has increased signicantly in Spain’s
neighbouring countries: Morocco (ve records
and c 15 additional reports not (yet) submitted;
Patrick Bergier pers comm), Portugal (13 records;
Jara et al 2011) and France (ve records, all in-
volving adult birds; CHN 2013). Recently, in May
2014, one was recorded in Israel (Dutch Birding
36: 198, plate 242, 2014). However, the majority
of records still originates from Spain, where
Rüppell’s now occurs annually. Up to 2013, there
have been 75 records representing 94 individuals
(Gutiérrez et al 2010, Copete et al 2015), and
around 40 more records since then which are cur-
rently under consideration. Additionally, there is a
remarkable number of sightings that have not
been ofcially reported. It is estimated that up to
20 different individuals have occurred around the
Strait of Gibraltar within a single year, and a few
groups of ve to six birds have been recorded.
Since 2015, Rüppell’s is no longer considered by
the Spanish rarities committee (CR/SEO).
As rst proposed by Gutiérrez (2003), and later
conrmed by eld observations at the Strait of
Gibraltar, the natural arrival of Rüppell’s Vulture to
western Europe results from their association with
the Griffon Vultures that disperse annually in win-
ter from the Iberian Peninsula to the African Sahel
(mainly Senegal), where Rüppell’s is widespread
(eg, Dutch Birding 33: 395, plate 514, 2011).
Rüppell’s reach the Iberian Peninsula via the Strait
of Gibraltar mainly from late spring to mid-sum-
mer. Once in the peninsula, they show a high mo-
bility, and despite a signicant concentration of
records in the vicinity of the Strait of Gibraltar,
Rüppell’s has also been recorded in most major
areas where Griffons occur, including the north-
ern Atlantic coast. From late September to mid-
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
555 Rüppell’s Vulture / Rüppells Gier Gyps rueppelli,
third plumage, Tarifa, Spain, 6 February 2011 (Paco
Guerrero Roldán). Primary moult has progressed and
bird also shows extensive replacement in secondaries
and tail.
352
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
556 Rüppell’s Vulture / Rüppells Gier Gyps rueppelli, old immature, Saint Louis, Senegal, January 2013 (Yeray
Seminario/Birding The Strait). Older birds can be similar to either second-plumage birds or more classic ‘white’
adults, depending on extent of patterning. Ordered moult sequence and worn p4 indicate this bird has third-genera-
tion (p1-3) and second-generation (p4-10) primaries; adults show disordered moult, alternating new and worn prima-
ries. 557 White-backed Vulture / Witruggier Gyps africanus, juvenile, Yabelo, Ethiopia, 4 January 2013 (Daniel
López-Velasco). Note more nely streaked plumage and duller grey greater coverts than in Rüppell’s Vulture G ruep- ruep-ruep-
pelli. Note that p1 has been dropped in both wings.
353
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
558 White-backed Vulture / Witruggier Gyps africanus, second plumage, Tarifa, Spain, 7 September 2008 (Markus
Varesvuo). Bird showing typical moult of second-plumage birds, with fresh inner primaries. Otherwise, plumage
similar to juvenile. 559 Griffon Vulture / Vale Gier Gyps fulvus, juvenile, Tarifa, Spain, 11 October 2013 (Javier
Elorriaga/Birding The Strait). Note extremely long wings, as well as prominent and typically closed tail.
354
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
November, a remarkable occurrence of Rüppell’s
takes place in the Strait of Gibraltar, in association
with juvenile Griffons concentrating there in large
numbers before their departure to Africa. It has
been documented that a majority of the Rüppell’s
that reach Europe successfully return to Africa (eg,
Ramírez Román 2012). However, a few individu-
als stay into the winter.
The age-class composition of the Rüppell’s
Vultures in Spain is intriguing. Most individuals
are in second plumage (ie, born the year before
their arrival to Europe), while older individuals
and juveniles are remarkably scarce. As an illus-
trative sample, of the 44 individuals with positive
age determination recorded in Spain in the period
2011-14, three were juvenile (7%), 33 were in
second plumage (75%), four were in third or
fourth plumage (9%), and four were adult (9%).
The explanation of this pattern is likely found in
the breeding phenology of the species. According
to Wacher et al (2013), Rüppell’s in the Sahel
breed slightly earlier (roughly one to three months)
than Griffon Vultures in Spain, and most juveniles
edge in May. The return migration of Griffon in
the Strait of Gibraltar is concentrated in May, with
a few groups arriving from late February to early
July. Accordingly, when the bulk of Griffon leaves
the Sahel (presumably in mid-April), most young
Rüppell’s have not yet edged. Therefore, only
second-year or older Rüppell’s join the groups of
Griffon on their northbound migration. The occur-
rences of juveniles could involve extremely early
edglings that become associated with the latest
migrant Griffon. This hypothesis is consistent with
the observation of several fresh juvenile Rüppell’s
reaching Gibraltar in July (eg, Garcia & Bensusan
2006). Meanwhile, the scarce records of adult
Rüppell’s in Europe should be interpreted as per-
sistent resident mature individuals, which might
have originally reached Europe as immatures. This
idea ts well with the proportionately higher oc-
currence of adults in regions further away from
the Strait of Gibraltar, mostly around Griffon colo-
nies, for example in France where most records
referred to adults.
White-backed Vulture
There have been four records of White-backed
Vulture in Spain, all near the Strait of Gibraltar, on
7 September 2008, 25 June 2009, 19 September
2011 and 17 June 2016, and single records in
southern Portugal and northern Morocco (both in
2014, on 24-25 August and 25 May, respectively;
cf El Kamlichi et al 2014, Godino & Machado
2015); a record of an adult in Portugal in October
2006 was accepted in Category D (cf Small 2007).
All six records involved second-plumage birds.
Despite the limited number of records, the emerg-
ing pattern is similar to that described for Rüppell’s
Vulture. However, White-backed is associated
with rather forested areas, being much rarer than
Rüppell’s in the northern part of the Sahel and
nearly absent along the edges of the Sahara desert.
Due to this distribution, despite being regarded as
the most abundant vulture in Africa, it is less likely
to be attracted to migrant groups of Griffon
Vultures, and therefore is a rarer vagrant to Europe
than Rüppell’s.
Future records
Due to the physical limitations for vultures cross-
ing large stretches of open water (Bildstein et al
2009), their arrival in the WP from Africa is prob-
ably restricted to both extremes of the Medi-
terranean Sea (Strait of Gibraltar in the west and
560 Griffon Vulture / Vale Gier Gyps fulvus, third plum-
age, Tarifa, Spain, April 2015 (Javier Elorriaga/Birding
The Strait). Griffon usually moults p5 during spring/early
summer of second moult-cycle, in contrast to African
vulture species which typically replace p5 earlier,
around September, within their rst moult cycle. For this
reason, replaced inner primaries present gradually wear
in Griffon, as opposed to Rüppell’s Vulture G rueppelli
and White-backed Vulture G africanus in which they
look more uniform.
355
Israel, Lebanon and Syria in the east). Once ar-
rived, rather regular long-distance movements of
immature Griffon Vultures along the Mediterranean
arch are known to occur (eg, birds from the Iberian
Peninsula reach central France and the Netherlands
(including colour-ringed birds) and birds from the
Balkan reach Israel and Italy). Therefore, there is a
potential for extreme vagrancy of the African vul-
ture species wandering in Europe together with
Griffon.
Several factors may determine the future vagran-
cy patterns of these species. The future trends of the
Griffon Vulture population in Europe and, more im-
portantly, its migratory behaviour to Afri ca, may
signicantly inuence the arrival of African spe-
cies. However, the extremely rapid human-induced
decline of vulture populations in West Africa will
undoubtedly be the most decisive factor. Rüppell’s
Vulture has already disappeared from large regions
and White-backed Vulture declines have exceeded
90% (Thiollay 2006). Given this trend, it seems
likely that the occurrence of African vultures will
decrease in the WP.
Ageing and ight-feather moult
Accurate age determination based on the state of
moult, including plumage wear, and correct as-
sessment of the corresponding body plumage, is
crucial for a reliable identication, particularly in
non-adult or tricky individuals. Ageing vultures in
the eld is feasible by looking at the combination
of several characters that differ between age class-
es (eg, Duriez et al 2011). These features, summa-
rized in table 1, provide an age classication into
three major groups: juvenile, immature and full
adult. In general, juveniles show a dark lanceo-
lated ruff and pointed greater upperwing-coverts,
whereas full adults show a whitish downy ruff and
round-tipped wing-coverts. Immatures (ie, from
the rst moult onwards) and subadults gradually
acquire mixed and intermediate characters. It
must be noted that White-backed Vulture shows a
black bill (including cere) and dark iris in all ages,
while Rüppell’s Vulture and Griffon Vulture gradu-
ally shift from blackish in juvenile to pale in adult.
More precise ageing requires a detailed study of
the moult pattern, and particularly the moult of
the ight-feathers. In general terms, the three spe-
cies follow the same moult sequence characteris-
tics of large Accipitridae (cf Houston 1975,
Forsman 1999, Newton 2009). Moult in Griffon
and its application to ageing has been compre-
hensively described by Zuberogoitia et al (2013).
We describe it here to provide a helpful baseline
that is applicable to the African species.
Because African vultures start breeding around
October-November, whereas Griffon Vultures start
in January-February, birds from the same season
correspond with different calendar-years.
Therefore, in this paper we use the classication
of plumages rather than calendar-year (as used by
previous authors). In the case of Griffon, juvenile
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
TABLE 1 Key of ageing in Gyps vultures, generally applicable to all species unless otherwise stated in main text. See
Duriez et al (2011) and Zuberogoitia et al (2012) for further information. White-backed Vulture G africanus maintains
blackish iris and bill colour during adult stage. / Sleutel voor leeftijdsbepaling bij Gyps gieren, meestal toepasbaar op
alle soorten, tenzij anders aangegeven in tekst. Zie Duriez et al (2011) en Zuberogoitia et al (2012) voor meer infor-
matie. Witruggier G africanus houdt zwartachtige iris en snavel als adult.
juvenile immature adult
bill uniform dull brownish as juvenile but developing pale creamy or ivory
close to upper bill edge (not in White-backed)
ruff brownish, concolorous with as in juvenile during rst four creamy or white
body-feathers years of life
iris black blackish until c fourth year of life pale (not in White-
backed)
feather shape long, narrow and pointed after rst moult, as in adult rounder, shorter and
(especially obvious broader than in juvenile
in greater coverts)
moult ight-feathers jet black blocks of new and old feathers new (black) and old
with uniform trailing edge involving many feathers; eg, (brownish) primaries
in second plumage, 3-4 inner alternated, with at most
black and 6-7 outer brownish 2, rarely 3, of same age
in row
356
plumage corresponds with birds without primary
moult, which lasts until May of the second year of
life; second plumage corresponds with birds be-
tween May of the second year and May of the
third year of life, when the second moult cycle
starts; and so on. The classication is analogous in
the African species, although the rst primary
moult and transition between plumages starts in
December-January in the African vultures.
Griffon Vulture
The rst moult starts c 14 months after hatching,
around May of the second calendar-year, and it is
arrested by December. The moult of primaries (p1-
10) starts from the innermost (p1), progressing
outward in an orderly fashion. It normally involves
the replacement of two to four of the innermost
primaries. The moult of the secondaries starts
around mid-summer, from different foci and in-
volving just a few feathers, and indeed individ uals
with no secondary moult are not rare. Moult
resumes by late April of the third calendar-year,
continuing with the feather next to the last one
moulted in the previous season. On average the
next four juvenile primaries are replaced, reach-
ing c p6-8. In some cases, p1 is also replaced
within this moult. The moult of the secondaries is
much more extended in this season, involving a
large proportion of the feathers. By December,
when the moult is arrested, most individuals still
show a few retained juvenile primaries in the
wing-tip and retained secondaries interspersed in
the inner half of the wing. In subsequent moult
cycles, again extending from late April to
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
FIGURE 1 A-C: Griffon Vulture / Vale Gier Gyps fulvus; D-G: Rüppell’s Vulture / Rüppells Gier G rueppelli (D-G); and
H-J: White-backed Vulture / Witruggier G africanus (Guillermo Rodríguez). Size roughly equalized in all photographs
in order to emphasize silhouette differences. Compare uniform trailing edge and distinctive silhouette of juveniles
(A, D, E and H) with older birds, especially with more squared-winged adults (C, G and J, although the latter is old
immature). In all plumages, extremely long wing of Griffon evident, and ‘open hand’ provides rectangular wing-
shape that is especially different from that of White-backed. Differences in bulkiness also noticeable in ight, par-
ticularly eye-catching in slim White-backed. Finally, note pale ‘commas’ on primary coverts of fresh juvenile Rüppell’s
(D), which is much less obvious in older bird (E), partially due to wear.
A
B
C
D
E
F
G
H
I
J
357
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
561 Three Gyps vultures (right): Rüppell’s Vulture / Rüppells Gier G rueppelli, adult (left), Griffon Vulture / Vale Gier
G fulvus, second plumage (centre), and White-backed Vulture / Witruggier G africanus, juvenile, Saint Louis, Senegal,
15 January 2013 (Yeray Seminario/Birding The Strait). Griffon is bulkier and more massive compared with other two
species, particularly White-backed. Note characteristic black mask of White-backed due to absence of feathering
around face, as well as pale greater coverts in juvenile plumage. Hooded Vulture / Kapgier Necrosyrtes monachus on
far left. 562 Rüppell’s Vulture / Rüppells Gier Gyps rueppelli, second plumage (front), and Griffon Vulture G fulvus,
juvenile, Tarifa, Spain, 10 June 2005 (David Cuenca). These birds were seen landing after arriving directly from
Africa. Compare typical long-billed impression of Rüppell’s with more triangular head of Griffon. Note also extensive
body moult of second-generation feathers in Rüppell’s.
358
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
December, the remaining juvenile feathers, which
are notably worn, are replaced and full adult
plumage is acquired. Adults moult within the
same period of the year; their moult does not fol-
low an evident pattern but they show a mixture of
alternating new and old feathers. Finally, migra-
tory individuals seem to perform a faster moult
during their rst one or two winter seasons in
Africa compared with resident birds (pers obs),
making the ageing of certain birds more compli-
cated.
Rüppell’s Vulture
Unlike Griffon Vultures in Iberia but similar to
many other Afrotropical species, non-adult
Rüppell’s Vultures apparently moult year-round,
probably lacking a xed moult schedule. Based
on our observations in Africa, primary moult usu-
ally starts in December-January. Second-plumage
Rüppell’s reaching the Iberian Peninsula in spring
(roughly 16-18 months old in May) have replaced
the innermost one to three juvenile primaries but
generally no secondaries. By September, the pri-
mary moult at this age normally has reached p4 or
563 Rüppell’s Vultures / Rüppells Gieren Gyps rueppelli, juvenile (below) and adult, Gadabeji, Niger, 2 August 2014
(Thomas Rabeil/SCF). Some juvenile Rüppell’s are pale and remarkably unstreaked, resembling Griffon Vulture
G fulvus. Note characteristic planar head prole. 564 Griffon Vulture / Vale Gier Gyps fulvus, Cadiz, Spain,
13 October 2009 (John Wright). This image demonstrates the huge plumage variability exhibited by Griffon, includ-
ing grey, rusty, and deep brown birds.
359
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
565 Rüppell’s Vulture / Rüppells Gier Gyps rueppelli, in second plumage, Ceuta, Spain, 16 May 2011 (José María
Cárceles/avesdeceuta). Compare long and more pointed juvenile feathers (though extremely worn) with pattern of
second-generation feathers. Note also details of red neck skin, white down in wing, forming characteristic wing-bar, and
paling of bill edge already apparent at this age. 566 Rüppell’s Vulture / Rüppells Gier Gyps rueppelli, second plumage,
Tarifa, Spain, October 2014 (Javier Elorriaga/Birding The Strait). Upperside showing classic patterned upperwing and
rump. Note also typical moult pattern, although this bird showing unusually extensive moult in tail-feathers.
360
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
A
B
C
D
E
F
FIGURE 2 A-C Griffon Vulture / Vale Gier Gyps fulvus, second plumage, third plumage and juvenile, respectively,
Dadia National Park, Greece, October 2003 (Javier Elorriaga/Birding The Strait); D Rüppell’s Vulture / Rüppells Gier
G rueppelli, juvenile, Mourao, Portugal, 9 June 2013 (Alfonso Godino); E Rüppell’s Vulture / Rüppells Gier G rueppelli,
immature, Tarifa, Spain, 4 October 2008 (Javier Elorriaga/Birding The Strait); F White-backed Vulture / Witruggier
G africanus, second plumage, Tarifa, Spain, 25 June 2013 (Javier Elorriaga/Birding The Strait). Details of diagnostic
pattern of greater coverts. Juvenile Griffon shows extensive variation, from entirely white (A) to almost completely
black (C), and though even in latter they usually retain diffuse pale edge. In immatures and adults, feather, though
still variable, usually white fringed with sharper transition from white to black (B). Note that white edge surrounds
entire feather. In Rüppell’s, pale fringe restricted to feather-tip (D) and lacking on lateral edges; it is just a spot in
juveniles but becomes broader line in older birds. Remarkably, pale markings are sandy tinged, not snowy white as
in Griffon. However, worn greater coverts can lack pale markings (E). Note also larger size of spot on innermost
secondaries. This pattern produces ne, well dened line along wing, both on upperwing and underwing. Immature
White-backed always exhibits dull greyish greater coverts, lacking any pale markings (F).
361
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
p5 (40% and 60%, respectively, based on 20
birds; pers obs) and the moult of the secondaries
starts from different foci. In third-plumage indi-
viduals in September, primary moult typically has
reached p9, most of the secondaries have been
replaced, and the retained juvenile feathers are
heavily abraded.
White-backed Vulture
North of the Sahara (at the Strait of Gibraltar), the
only two individuals for which the moult state was
determined were two second-plumage individu-
als in which the moult limit reached p4 (nearly
full-grown) and p5 (recently shed; see plate 558)
in late June and early September, respectively. The
observations t well with the typical pattern of va-
grant Rüppell’s Vulture.
Summary
In summary, immature African vultures in Europe
show an advanced moult compared with Griffon
Vulture. This asynchrony may help identication;
the presence of a uniform block of moulted p1-5
in autumn (around September), looking very fresh
and contrasting with the faded outer primaries,
strongly points to an African origin. In a second-
plumage Griffon, the moult limit in September
generally reaches p2-3. Some Griffon may show
the moult limit reaching p5 in September as well
but this would imply, in most cases, third-plumage
birds. Thus, the set of moulted feathers belongs to
two different annual moult cycles, in which the
innermost primaries (moulted in the rst cycle)
may show a notably higher degree of wear than
the outer feathers replaced during the current sec-
ond cycle (see plate 560 and compare with plate
554 and 566).
Species descriptions
Griffon Vulture
Size and structure
Griffon Vulture is a large vulture, looking notori-
ously heavy and bulky both in ight and perched.
It has very long wings and tends to hold the pri-
maries well separated from each other (looking
like an ‘open hand’), resulting in a rectangular
wing shape. Juveniles typically show a slightly
rounder trailing edge to the wing than adults. In
ight, the tail-base is separated from the wings, so
that part of the rump is usually visible in the sil-
houette; the tail is often kept closed, making it
quite prominent in the ying silhouette.
Griffon Vulture has a strong neck with a heavy
A
B
C
FIGURE 3 A Griffon Vulture / Vale Gier Gyps fulvus, Pais
Vasco, Spain, 13 August 2005 (Iñigo Zuberogoitia);
B Rüppell’s Vulture / Rüppells Gier G rueppelli, imma-
ture, Tarifa, Spain, 4 October 2008 (Javier Elorriaga/
Birding The Strait); C White-backed Vulture / Witruggier
G africanus, Tarifa, Spain, 25 June 2009 (Javier Elorriaga/
Birding The Strait). Details of upperwing. Note plain
upperwing-coverts in Griffon and characteristic pattern
of greater coverts, with sandy edge surrounding the
feather prole. In comparison, in Rüppell’s, pale mark-
ings restricted to tip and lacking on lateral feather-edges,
and vary from pale line to triangular spot, conferring
typical patterned appearance. Compare also feather
shape, which is rounder and smaller in Rüppell’s. In
White-backed, although feathers are individually plain,
contrast between different generations often producing
slightly similar patterned appearance. Note pale colour
of greater coverts.
362
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
head. It is more square headed than the other spe-
cies. The front slope is pronounced and not con-
tinuous with the bill, forming an angular (concave)
front prole. Nonetheless, a certain degree of sex-
ual dimorphism in head shape exists and females
show a slightly rounder head shape.
Head and neck
The down colour is white and it densely covers
the entire neck and head but a hint of facial mask
is sometimes present due to the greyish (or in
adults, more bluish) skin showing through areas of
absent (or less dense) down, especially behind the
eyes and auriculars.
Bare parts
The crop is dark brown-grey. The circular bare
patch at the side of the neck base (typical of the
genus Gyps) is greyish-blue, although the colour is
variable, sometimes appearing deep red or bicol-
oured red/blue, apparently depending on the bird’s
condition or stress (currently not clearly known).
The tarsus is dull greyish, although it can be brown-
tinged in young birds, individually variable, or af-
fected by dirt. The bill is dark in juvenile and sec-
ond plumages and develops small pale patches
during the third plumage; it only becomes pre-
dominantly pale from the fourth plumage onwards.
The iris colour remains dark during the rst years
of life but is very pale in adult birds.
Main plumage
Juvenile and immature plumages are similar over-
all in Griffon Vulture, and accordingly they are
treated here together. The main differences are
found in the shape of the feathers, being long and
pointed in juveniles and more square in older
birds, particularly in the greater coverts (these age
differences likewise apply to the other species).
The overall coloration is usually sandy or griffon
but see ‘Discussion’.
Typically, the body-feathers are plain in all
plumages but some Griffon Vultures (especially
juveniles) show a ne streaking. The appearance
of a streaked body in these birds can lead to po-
tential misidentications as juvenile White-backed
567 Rüppell’s Vulture / Rüppells Gier Gyps rueppelli, juvenile, Tarifa, Spain, 11 September 2013 (Javier Elorriaga/
Birding The Strait). Note small pale spots on greater coverts and primary coverts, otherwise generally very similar to
White-backed Vulture G africanus and, to lesser extent, Griffon Vulture G fulvus. 568 White-backed Vulture /
Witruggier Gyps africanus, second plumage, Yabelo, Ethiopia, 4 January 2013 (Guillermo Rodríguez). Moulted p1
indicates age. Note completely dull, washed out greater coverts. Small head and characteristic facial pattern usually
obvious.
363
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
Vulture or Rüppell’s Vulture (see plate 569). When
present, the streaks in Griffon are usually ner
than in the other species. The upper back is plain
and concolorous with the body and wing, where-
as the rump-feathers are black with wide pale
fringes. In general, these dark feathers are devel-
oped after several moults; they are lacking in juve-
niles, whereas (possibly older) adults may show a
completely scaled dark back. The lesser coverts
and median coverts are concolorous with the
body, while the primaries are contrastingly black.
The pattern of the greater coverts changes signi-
cantly with age. In juveniles, the feather is pointed
and pale tipped, showing a diffuse transition be-
tween dark centre and creamy fringes. In subse-
quent plumages, the greater coverts are round
tipped with a black centre and show a pale fringe
all along the feather contour, showing a more dis-
tinct contrast than in juveniles but still not mark-
edly sharp. The pale fringe is concolorous with the
lesser coverts and median coverts. The primary
coverts and alula feather are plain black. The less-
er coverts and median coverts are plain and con-
colorous with the body, while the primaries are jet
black. In contrast, the greater coverts and primary
coverts are bicoloured whitish-black but are very
variable, ranging from uniform white (especially
in juveniles) to nearly all black. In most adults and
immatures, however, these feathers show a black
centre with diffuse white fringe. Like the other
species, Griffon lacks feathers in a small patch in
the lesser to median coverts limit, close to the
body, and the white down that is exposed beneath
forms a short white ‘wing bar’. The axillaries are
plain and concolorous with the body.
Rüppell’s Vulture
Size and structure
Rüppell’s Vulture is smaller than Griffon Vulture
(roughly 30% in weight; Ferguson-Lees & Christie
2001), and it generally looks slimmer and less
bulky bellied. When perched, it often looks slight-
ly humpbacked. In ight, it has a slim body but
medium-long wings that are not strikingly shorter
than in Griffon. The wing shows a clear narrowing
569 Rüppell’s Vulture / Rüppells Gier Gyps rueppelli, juvenile, Tarifa, Spain, 15 September 2013 (Javier Elorriaga/
Birding The Strait). In few individuals, pale markings on greater coverts and primary coverts almost absent. This bird,
although resembling White-backed Vulture G africanus in plumage, can be identied by more powerful structure.
570 Griffon Vulture / Vale Gier Gyps fulvus, third plumage, Skåne, Sweden, 21 July 2013 (Tommy Holmgren). Griffon
can be streaked in all plumages and although not as heavily marked as two other species, pattern can sometimes be
confusing.
364
571 Griffon Vulture / Vale Gier Gyps fulvus, adult (left), and White-backed Vulture / Witruggier G africanus, second
plumage, Tarifa, Spain, 7 September 2008 (Markus Varesvuo). Direct comparison provides straightforward identica-
tion due to much larger size of Griffon. Note differences, including more delicate silhouette in White-backed, with
slender wing. 572 Griffon Vulture / Vale Gier Gyps fulvus, juvenile (top), and Rüppell’s Vulture / Rüppells Gier G ruep- ruep-ruep-
pelli, second plumage, Tarifa, Spain, 8 October 2010 (Pako Zuaur). Compare typical wing position of Rüppell’s with
closed hand pointing backwards with squarer wing and massive body of Griffon. 573 Griffon Vulture / Vale Gier Gyps
fulvus, adult (top), and Rüppell’s Vulture / Rüppells Gier G rueppelli, adult, Tarifa, Spain, 28 October 2013 (Yeray
Seminario/Birding The Strait). In adult plumages, differences are generally less accentuated, although note shorter
wings of Rüppell’s.
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
365
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
from the arm to the hand and birds tend to soar
with the hand held closed, so that the outer pri-
maries are not well-marked and when gliding are
typically oriented backward. This position pro-
duces a rounded wing tip in distant views. Adults
show a more square-winged silhouette than young
birds. Compared with Griffon, Rüppell’s has an
apparently shorter distance between the tail and
wing-base, so that in ight the base of the trailing
wing edge and the outermost tail-feather overlap.
They also tend to hold their tail open, making it
look less prominent in the silhouette than in
Griffon and resulting in a ‘short-tailed’ impres-
sion. These differences in size and structure sepa-
rating Griffon from the other two species are,
however, rather subtle and require some experi-
ence (see gure 1).
Rüppell’s Vulture has a at head prole with a
rather even transition between the bill and front
slope. This is compounded with the comparatively
slender bill to produce an accentuated long-billed
impression (as shown in plate 562).
Bare parts
The crop is blackish, similar to White-backed
Vulture but darker on average than in Griffon
Vulture. The circular bare patch is blue/greyish as
in Griffon. The tarsus is dark brown, with some
variation between individuals; it is not a reliable
characteristic for separating Rüppell’s Vulture from
Griffon (but see White-backed). The neck skin is
brownish around the head and strikingly deep red
on the lower part of the neck. The down colour is
white. The bill tends to become pale at an earlier
age than in Griffon, with a few second-plumage
birds already showing pale patches, although
more typically the pale regions are developed
during the third plumage.
Juvenile plumage
Juveniles are profusely streaked and brown over-
all, usually darker in colour than Griffon Vulture
and often slightly rufous-tinged. They have dense
brown ruff, darker than the other two species, as
well as a black bill and eye.
The entire body is thickly streaked, with streaks
574 Griffon Vulture / Vale Gier Gyps fulvus, adult, Tarifa, Spain, 27 February 2015 (Fernando Goytre). Example of
‘scaled’ Griffon, showing second line of pale-fringed wing-coverts. Back also abnormally dark and particularly
streaked below. Compare with Abyssinian Rüppell’s Vulture G rueppelli erlangeri in plate 575, noting especially dif-
ferences in pattern of scaled greater coverts and median coverts. 575 Abyssinian Rüppell’s Vulture / Abessijnse
Rüppells Gier Gyps rueppelli erlangeri, adult, Awash, Ethiopia, 11 November 2012 (Fran Trabalon)
366
formed by the creamy shaft and centre of the
feather contrasting with the darker surrounding
colour. Around the feather-tip, the pale colour
also extends to the lateral fringes, producing an
‘arrow’ or ‘anchor’ pattern, which is particularly
visible in the undertail-coverts. The back and
rump are concolorous with the body and upper-
wing. Here, the streaking is less contrasting or
even absent. On the upperwing, the lesser and
median coverts are concolorous with the body-
feathers but are plain or rarely nely streaked. The
primaries and secondaries are blackish, creating
only a moderate contrast with the wing-coverts.
The pointed and dark brown greater coverts are
pale tipped (typically creamy or sandy). On the
underwing, the lesser coverts are concolorous
with the body-feathers but very nely streaked.
The median coverts are similar but with thicker
streaks and feather-tip, and are slightly darker. The
greater coverts are dark brown and unstreaked but
show a small white spot at the tip. This spot is
much larger in the primary coverts, sometimes
forming a ‘comma’ like in Greater Spotted Eagle
Aquila clanga. The white bar in the wing is broad-
er than in the other species. The axillaries are long
and darker than the surrounding feathers, and
therefore the pale ‘anchor’ pattern is usually more
contrasting and well dened.
Immature plumages
After the rst body moult, Rüppell’s Vulture loses
its streaked juvenile plumage and immatures are
dark and spotted overall. When second-plumage
individuals arrive in Europe in late spring, they are
usually nishing this rst moult of the body-feath-
ers. In subsequent moults, the spots become in-
creasingly larger and some mature adults have a
heavily patterned plumage. A dark brown ruff is
maintained for at least the rst three plumages.
In addition to having a squarer shape than juve-
nile feathers, the second-generation body-feathers
maintain a pale central line but with a broader
spotted tip, so that the pattern now resembles a ‘T’
rather than an anchor. They look ‘streaked and
spotted’ overall (see plate 565). In third-plumage
individuals, the central streak tends to disappear
and the pale tip becomes larger, conferring the
characteristic patterned appearance of the spe-
cies. In subsequent moults, the pale white tips in-
crease gradually in size, eventually acquiring the
large V-shaped spots of adults. The feathers of the
back and rump are blackish, sometimes contrast-
ing with the paler wing. They also show the char-
acteristic V-shaped pale tip, contrasting sharply
with the rest of the feather. The feathers of the
uppertail-coverts (except of the last line) are strik-
ingly small and round, resulting in a high feather
density (eg, plate 566) that differs from Griffon
Vulture. On the upperwing, all wing-coverts are
dark centered with a sandy V-shaped tip and they
are also smaller and rounder than in Griffon. On
the lesser coverts, the pale tip is dominant and
only the pale area of the feather is exposed; on the
median coverts, it is proportionally smaller and
the dark base is visible, forming a heavily scaled
area. On the greater coverts and primary coverts,
the pale tip is just a ne line, and the feather looks
basically blackish. Unlike in Griffon, the pale
fringe is restricted to the tip and invariably not
present on the lateral edges (ie, it is not complete).
On the underwing, the wing-coverts are concolor-
ous with the body-feathers. The lesser coverts are
plain and unstreaked. The median coverts have a
thick streak and a small white tip in second-plum-
age birds (plate 565); in third plumage, the streak
is absent and the white tip is larger. The greater
coverts are darker and unstreaked and show a dis-
tinctive white tip, forming a short line on imma-
tures due to the square feather shape, in contrast
with the white spot that is on the pointed juvenile
greater coverts. This line on immatures becomes
thicker in subsequent moults, forming a well-de-
ned white bar across the entire wing. The combi-
nation of dark wing-coverts and abraded brown-
ish primaries results in a low (often unnoticeable)
contrast on the underwing.
White-backed Vulture
In this species, there are marked differences be-
tween the young plumages (which are similar to
either juvenile Rüppell’s Vulture or Griffon Vulture)
and adults. The characteristic white back and un-
derwing of adults are not developed until roughly
the fourth plumage.
Size and structure
White-backed Vulture is a small vulture, roughly
50% and 30% smaller than Griffon Vulture and
Rüppell’s Vulture, respectively (Ferguson-Lees &
Christie 2001). It looks slimmer and lighter than
the other two species. In ight, White-backed is
short-winged due to comparatively short prima-
ries, looking more compact than Griffon or Rüp-
pell’s. The wing clearly narrows from the arm to
the hand. Like Rüppell’s, White-backed usually
holds the hand closed, with all the outer primaries
kept together and not as differentiated as in
Griffon. Juveniles show a markedly rounded trail-
ing edge to the secondaries, a feature that is like-
wise shared with Rüppell’s but is less obvious in
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
367
FIGURE 4 White-backed Vulture / Witruggier Gyps africanus (A) and Rüppell’s Vulture / Rüppells Gier G rueppelli
(B-D). Detail of tails. White-backed has 12 tail-feathers; both Rüppell’s and Griffon Vulture G fulvus have 14.
A: although r2 missing in this individual and r4 broken, 11 feathers clearly visible. B-C: in both these Rüppell’s,
13 tail-feathers can be counted; 14th feather must be hidden or moulting. D: 14 tail-feathers visible in this uppertail
view, although one or two difcult to see and probably not visible from below.
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
Griffon. The neck is notably slender and less pow-
erful than in the larger vulture species. The head
has a characteristic triangular shape.
Head and neck
The head exhibits a conspicuous black mask due
to the complete absence of down covering ex-
tending from the lore through the eye area and
auriculars. Only in a few juveniles is the mask
lacking or restricted to just the lore.
Bare parts
The crop is jet black and the circular bare patches
are sometimes strikingly yellow. The black tarsus
has traditionally been considered an important
identication feature, compared with the greyish
tarsus of the other two species (van Duivendijk
2010). We consider this feature to be of limited
use and only applicable to birds with an extreme-
ly black tarsus. The actual tarsus colour is often
dark greyish, and not markedly different from that
of immature Rüppell’s Vulture or, to a lesser ex-
tent, Griffon Vulture. The bill is short and remains
black, including the cere, even in adults. The skin
is dark brown or blackish, and the down colour
usually looks dirty compared with the other spe-
cies. It retains a dark iris colour with age.
Juvenile plumage
Juveniles are darker than immature and adult
birds, and are often similar to or even darker than
the average juvenile Rüppell’s Vulture. In general,
some juveniles are extremely similar to Rüppell’s
and their identication relies on subtle details.
A
B
C
D
368
576 Rüppell’s Vulture / Rüppells Gier Gyps rueppelli, juvenile, Tarifa, Spain, 5 September 2014 (Yeray Seminario/Birding
The Strait). Same bird as right bird in plate 552. In this image, pale markings on primary coverts and inner greater coverts
conrm that it is runt Rüppell’s but this bird would likely be misidentied as White-backed Vulture G africanus in more
distant views. 577 Griffon Vulture / Vale Gier Gyps fulvus, adult (back), and Rüppell’s Vulture / Rüppells Gier G ruep-
pelli, juvenile, Cadiz, Spain, 22 September 2009 (John Wright). Other example of small Rüppell’s, which could be dif-
cult to separate from White-backed Vulture G africanus because of ne body streaking and intermediate facial pattern.
Note slightly pale tipped greater coverts, although probably not marked enough to be diagnostic.
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
The body-feathers are streaked, with streaks of
intermediate width (ner than in Rüppell’s Vulture
and thicker than in Griffon Vulture), which are
also sometimes paler than in Rüppell’s. The streaks
are pointed, lacking any spot or anchor at the tip
and are concentrated on the belly and breast, be-
ing more diffuse on the upperparts. The back and
rump are plain and slightly browner than the
body-feathers and underwing. On the upperwing,
the lesser and median coverts are concolorous
with the body-feathers and are plain or at most
nely streaked. The greater coverts are also plain
and paler than in the other species, usually being
only slightly darker than the median coverts and
therefore contrasting with the dark brown prima-
ries. The wing often looks tricoloured. On the un-
derwing, the lesser and median coverts are nely
streaked and concolorous with the body-feathers.
The greater coverts and primary coverts are plain
and have a characteristic dull appearance, giving
a washed-out impression even when fresh, and
lacking any pale spot. The axillaries are concolor-
ous with the underwing-coverts. The ight-feath-
ers are dark but often with a distinct brown tinge,
369
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
578 Griffon Vulture / Vale Gier Gyps fulvus, adult, Tarifa, Spain, 3 September 2012 (Alan Gilbertson). Bird showing
large white stripes on underwing, contrasting with rather darkish plumage, causing potential confusion with Rüppell’s
Vulture G rueppelli. Note that white ruff indicates adult; adult Rüppell’s is expected to have visible patterning. Note
also typical structure with very long wings and tail and bulky body. 579 Griffon Vultures / Vale Gieren Gyps fulvus,
adults, Castellon, Spain, 19 March 2011 (José Luis Joanpere). Other example of dark adult Griffon which can lead to
misidentication, emphasized here by direct comparison with paler and much larger classic Griffon.
580 Rüppell’s Vulture / Rüppells Gier Gyps rueppelli, second plumage, Tarifa, Spain, 22 August 2013 (Yeray Seminario/
Birding The Strait). Uniform bird looking similar to dark Griffon Vulture G fulvus; however, narrow hand, short-tailed
impression and patterning on undertail-coverts when seen in detail clinch identication as Rüppell’s. 581 Griffon
Vulture / Vale Gier Gyps fulvus, second plumage, Tarifa, Spain, 13 October 2014 (Javier Elorriaga/Birding The Strait).
If not seen in ight, some birds can be difcult to separate. In this bird, relatively uniform upperwing and character-
istic head shape rule out Rüppell’s Vulture G rueppelli.
370
583 Abyssinian Rüppell’s Vulture / Abessijnse Rüppells
Gier Gyps rueppelli erlangeri, in third plumage, Debre
Libanos, Ethiopia, 6 November 2012 (Fran Trabalon).
This bird is steadily developing patterned body and un-
derwing of adult but still looks uniform overall. Note
characteristic white bar along wing formed by white tips
of feathers of greater coverts and primary coverts.
especially compared to the jet black that is char-
acteristic of Griffon. The white wing-bar is narrow
and short.
Immature plumages
Second-plumage birds are paler overall than juve-
niles. Although they retain the contrasting streak-
ing on the underparts, in second-generation feath-
ers the streaks are rather blunt, not pointed as in
juveniles. The streaking is, in addition, more dif-
fuse and sandy tinged. Other plumage features
remain similar to juveniles, including the under-
wing. Second-generation greater upperwing-cov-
erts and ight-feathers are now black. In third
plumage, it gradually acquires a sandy colour and
the streaking washes out, giving an ‘untidy’ im-
pression. In subsequent moults, they become in-
creasingly uniform. The development of white
feathers on the underwing, usually starting on the
median coverts and the upper rump, normally
takes place within the third or most commonly
fourth plumage.
Identication key
To facilitate identication, in this section we high-
light the usual impressions shown by a potential
vagrant African vulture, emphasizing the key fea-
tures. A systematic comparison of the important
features is presented in table 2.
Griffon Vulture versus Rüppell’s Vulture
Rüppell’s Vulture’s smaller size is not always strik-
ing in ight; it is more obvious on the ground but,
still, there is some overlap in apparent size. When
close examination is possible, differences in head
shape and particularly front slope (at or convex
in Rüppell’s versus angular and concave in Griffon
Vulture) are important, along with the deep red
skin of Rüppell’s, although Griffon stained by
blood can look similar. The silhouette is not very
distinctive (and it requires some experience) but
can be a supporting feature in certain circum-
stances. Juveniles, in general, are surprisingly in-
conspicuous in a Griffon ock, despite their heav-
ily streaked appearance. Immatures are more evi-
582 Abyssinian Rüppell’s Vulture / Abessijnse Rüppells
Gier Gyps rueppelli erlangeri, juvenile, Aledeghe Plains,
Ethiopia, 18 November 2012 (Nik Borrow). Some juve-
niles are plain and uniformly sandy, resembling Griffon
Vulture G fulvus. Note, however, typical Rüppell’s pat-
tern to greater coverts, axillaries and underwing coverts,
as well as silhouette.
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
371
dent due to their overall dark brown color and
patterned upperparts. In all plumages, Rüppell’s
have bicolored undertail-coverts ranging from
V-shaped fringes in juvenile to large white spots in
adult. Pale marking is also noticeable in the spot-
ted and dark axillaries, usually visible at large dis-
tances. The greater coverts pattern is diagnostic: in
Griffon, the pure white is usually extensive, not
showing a contrast with the dark feather centre,
and the white surrounds the entire feather edges;
in Rüppell’s, the pale area is sharply dened, re-
stricted to the feather-tip, and lacking on the lat-
eral edges. These differences are actually valid for
all patterned feathers of the wing and back.
Rüppell’s Vulture versus White-backed Vulture
Rüppell’s Vulture looks larger and bulkier but
there is some size overlap with White-backed
Vulture and the difference is not always notable,
especially in ight. The silhouette is similar in
both species, especially in juveniles. In resting
birds, the combination of a black mask and trian-
gular head in White-backed, instead of the long-
billed prole of Rüppell’s, is quite reliable. The
main identication problem occurs with the
streaked juvenile plumages. One diagnostic fea-
ture is the form of the streaks on the body-feathers
(particularly the axillaries and undertail-coverts):
White-backed shows just a line, lacking the ‘an-
chor’ pattern of Rüppell’s. Also, the presence of a
pale tip to the greater coverts, while characteristic
of Rüppell’s, immediately discards White-backed.
The number of tail-feathers (12 in White-backed
and 14 in Rüppell’s), as explained in the ‘Discus-
sion’ section, could be a key feature for clinching
the identication of difcult individuals. Immatures
are usually distinguished more easily due to the
darker coloration of Rüppell’s.
Griffon Vulture versus White-backed Vulture
Despite the strong size difference, evaluation of
size is often difcult and the difference only evi-
dent when the two species are side by side. The
silhouette is distinctive enough, with the slim,
more fragile impression of White-backed Vulture
and its narrow, closed hand contrasting with the
massive body and long, square wing of Griffon
Vulture. When perched, the black mask of White-
backed is a prime feature but beware of Griffon
that can have a faint darkish mask due to feather
loss. In all juvenile and immature plumages, the
presence of white marking in the greater coverts
TABLE 2 Key features for separation of Griffon Gyps fulvus, Rüppell’s G rueppelli and White-backed Vulture G afri- afri-afri-
canus in juvenile and immature plumage / Sleutelkenmerken voor onderscheid tussen Vale Gier Gyps fulvus, Rüppells
Gier G rueppelli en Witruggier G africanus in juveniel en onvolwassen kleed
Griffon Vulture Rüppell’s Vulture White-backed Vulture
silhouette long-winged, square wings, relatively short wings, closed short wings, closed
massive body hand, slim body hand, very slim body
head squared, bill dark until very long-billed, at forehead, triangular, short black
third/fourth plumage bill becomes pale during bill, jet black facial
second/third plumage mask
neck skin blue/greyish; blue circular deep red; blue circular patches black; often yellow
patches circular patches
body-feathers usually uniform although broad pale streaking with pale intermediate pale
(especially sometimes with ne pale spot at feather-tip (anchor in streaking lacking any
undertail-coverts) streaking juveniles) spot at feather-tip
greater coverts and from white to an almost black black with pale tip, particularly dull black with no
primary coverts feather, but always entirely evident in primary coverts; pale marking
pale fringe lacking lateral fringe
upperwing plain, uniform griffon/sandy scaled upperwing with several plain, uniform
except dark greater coverts rows of black pale-tipped sandy/brown with
with visible pale fringe feathers (greater and median uniform brownish
coverts) greater coverts
moult (birds in second plumage: fresh p1-2/3 second plumage: fresh p1-5 second plumage:
September in Spain) third plumage: fresh p5-6 third plumage: fresh p6-8 fresh p1-5
number of tail-feathers 14 14 12
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
372
or primary coverts (both on upperwing and under-
wing) immediately rules out White-backed.
During early summer and mid-summer, Griffon in
active moult often show an almost entire white
underwing, reminiscent of adult White-backed.
Discussion
Variability of key features
Plumage coloration
Juvenile and immature Griffon Vultures show a
considerable (and largely overlooked) variability
in their overall coloration, ranging from greyish-
brown to rusty or cinnamon, or even chocolate
brown (plate 564). Dark brown individuals, often
immatures, are frequently mistaken for immature
Rüppell’s Vultures. Even dark adults (especially in
underexposed photographs) are sometimes mis-
identied as Rüppell’s (plate 578). All in all, plum-
age colour is an eye-catching but far from diag-
nostic feature. Both Rüppell’s and White-backed
Vulture exhibit signicant variation in plumage
coloration as well (plate 563). Adult Rüppell’s also
have extensive variability in plumage pattern.
Some West African individuals are largely plain
brown with only a ne pale barring, giving a dark
appearance overall, while on the other extreme,
some heavily spotted individuals look predomi-
nantly pale.
Greater coverts in Rüppell’s Vulture
The greater coverts pattern is a diagnostic feature
in all three species. It is particularly relevant in the
identication of some small looking juvenile
Rüppell’s Vultures. Whereas the greater coverts
and primary coverts in East African Rüppell’s al-
ways show a large spot at the tip, in some West
African birds the pale tip is almost absent or re-
duced to just a small spot that is only visible with
close observation (eg, plate 569), which may
hinder a positive identication. The spot is usually
larger on outer primary coverts and axillaries (see
plate 576).
Wing-bar
Frequently pointed out as a diagnostic feature of
Rüppell’s Vulture (Svensson et al 2009, van
Duivendijk 2010), the underwing-bar is actually
present in all three species and is very variable,
especially in Griffon Vulture, where in many indi-
viduals this feature overlaps or exceeds the
amount present in the average Rüppell’s Vulture
(plate 578). Note that this feature also depends on
the extension of moult and, as previously men-
tioned, Griffon in strong active moult (mainly dur-
ing the summer) often show large white patches in
the wing.
Tail-feathers
White-backed Vulture is sometimes placed to-
gether with White-rumped Vulture in a separate
genus, Pseudogyps, because both species have
only 12 tail-feathers instead of the 14 characteris-
tic of the rest of the Gyps taxa. In some cases, the
number of tail-feathers could be a diagnostic fea-
ture for separating White-backed from both
Griffon Vulture and Rüppell’s Vulture. This feature,
however, must be carefully considered for a vari-
ety of reasons. First, any feather loss in Rüppell’s
or Griffon could be misleading and mistakenly
point towards White-backed. Second, the accu-
rate count of the tail-feathers of birds in ight is
often tricky, so the total count usually gives 12-13
feathers in Rüppell’s and 10-11 in White-backed.
However, even in these cases, White-backed gives
the impression of ‘having few tail-feathers’ (see
gure 4). Additionally, it has been suggested that
there is some individual variation, and not all vul-
tures may t the described number of tail-feathers
(Mundy et al 1992). These authors state that 20%
of White-backed diverge from the usual 12 tail-
feathers, although from 12 birds analysed we have
not found any bird exceeding the expected
number. In general, this character should be ap-
plied with caution in the eld.
Controversial cases
‘Scaled’ Griffon Vulture versus Rüppell’s Vulture
(plate 574-575)
A few adult Griffon Vultures show a second line of
dark, pale-fringed upperwing-coverts, in addition
to the greater coverts. Sometimes, the same pat-
tern is also observed in a few sparse lesser coverts.
The last line of median coverts is completely ex-
posed, showing a similar pattern to the greater
coverts and thus giving a scaled-wing impression,
resembling that of Rüppell’s Vulture. Moreover,
these birds also have a markedly scaled back, with
striking black-centred feathers, forming a dark
back contrasting with the wing. All these features
make these birds quite similar to adult Rüppell’s,
particularly to erlangeri, and these Griffon have
caused some online debate over birds from Spain
and Israel (Gordillo 2012; http://birdingfrontiers.
com/2014/11/02/ruppells-vulture-or-hybrid).
Identication is not difcult if one is aware of this
plumage variation, as the scaling in this plumage
is restricted to one line of median coverts (rather
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
373
than more extended along the entire wing as in
Rüppell’s), and the pattern of the feather is also
typical of Griffon, showing a diffuse pale fringe
along the entire feather contour. To our knowl-
edge, it is unclear whether scaled plumages are
associated with individual variation or related to
plumage development with age.
Abyssinian Rüppell’s Vulture
The taxonomic status of Rüppell’s Vultures in the
Abyssinian region (Ethiopia, Eritrea and Somalia)
is currently poorly understood. Some authors dis-
tinguish between the subspecies erlangeri in
Eritrea and northern Ethiopia, and nominate ruep-
pelli in the southern part of the latter country (Ash
& Atkins 2009). Erlangeri is usually described as
paler than rueppelli but little is known about its
actual variability. It seems that Abyssinian Rüppell’s
present two distinct morphs, one brownish and
only partially different from birds from further
west and south, and a striking pale morph which
is very similar to Griffon Vulture, to the extreme
that a hybrid origin has been proposed (Forsman
2016). Given the singularity of these vultures, as
well as our limited experience with erlangeri, we
just offer some brief comments as an introduction
to its identication.
Erlangeri is, in several plumage aspects, inter-
mediate between Griffon Vulture and nominate
rueppelli, although structural aspects and silhou-
ette are not appreciably different from their west-
ern counterparts. Juveniles of erlangeri are plain
and sandy coloured, lacking any streaking, and
have a plumage extremely close to Griffon (for an
example of such controversial individuals, see
plate 582). Adults and immatures are browner and
more patterned than juveniles, although not as
strikingly as in nominate rueppelli (plate 583).
Specic plumage features such as the pattern of
the greater coverts or axillaries are usually similar
to those in nominate rueppelli.
Rüppell’s Vulture vagrants to the Middle East
are expected to originate from the northern area
of Ethiopia or further north (eg, Eritrea, South
Sudan and Sudan), where most Griffon Vultures
from Eurasia winter (Ash & Atkins 2009). Hence,
the aspect of potential vagrants to the Middle East
is actually uncertain, and perhaps the closer re-
semblance of these erlangeri to Griffon has ob-
scured the actual status in the region. Remarkably,
the only Rüppell’s recorded in Israel was quite
typical and not signicantly different from the
Iberian vagrants (Dutch Birding 36: 198, plate
242, 2014).
Potential hybridization in the WP
Hybridization in the wild has never been proven
within the genus Gyps. However, given their phy-
logenetic and ecological proximity and the prov-
en cases of hybridization in captivity (McCarthy
2006), the possibility of mixed pairing between
Griffon Vulture and Rüppell’s Vulture, even if very
unlikely, should not be disregarded, particularly
in an extralimital scenario (Hubbs 1955). In this
context, there are several cases in the Iberian
Peninsula that could indicate a likelihood of (fu-
ture) hybridization. 1 Between 1999 and 2007, an
adult Rüppell’s was regularly seen in a Griffon
colony in Portas de Rodao, Portugal (Caty et al
2010). In 1999, this bird was recorded presuma-
bly incubating, although its progress was not
monitored and no conspecics were observed.
Mixed pairing was therefore a possible explana-
tion. 2 In 2011, an immature Rüppell’s and an im-
mature Griffon were observed twice exhibiting
pairing behaviour (ie, mutual preening and neck
intertwining; Elorriaga & Gutiérrez 2011) in Cádiz,
Spain (video at http://tinyurl.com/z424cbo). This
could be interpreted either as the prelude of pair
formation or as just abnormal behaviour among
immatures. 3 A widely discussed adult vulture
photographed in Cáceres, Spain (Gordillo 2012),
showed putative mixed characters. However, the
characters shown were not conclusive and the ex-
planation of an aberrant individual seems likewise
acceptable.
Acknowledgements
We thank all photographers who kindly provided pic-
tures, either for publication or study. We are particularly
grateful to Sabrina Hepburn and Yeray Seminario for
their comments and improvement of the manuscript.
Dick Forsman has provided over the years interesting
advice and discussion about these vultures. Finally, we
thank Joaquín Mazón for sharing his novel ideas and
knowledge about the presence of Rüppell’s Vulture in
Spain.
Samenvatting
De t e r m i n a t i e v a n rüp p e l l s Gi e r e n Wi t r u G G i e r en v o o r -
k o m e n a l s D Wa a l G a s t i n D e Wp Rüppells Gier Gyps ru-
eppelli verschijnt regelmatig in Zuidwest-Europa en
Witruggier G africanus is er een aantal keren als dwaal-
gast vastgesteld. Hoewel van beide de determinatie en
het onderscheid van Vale Gier G fulvus doorgaans een-
voudig is in adult kleed, kan de herkenning van juve-
niele en onvolwassen kleden lastig zijn.
In dit artikel wordt het voorkomen in de WP van de
twee Afrikaanse gierensoorten besproken, waarbij dui-
delijk wordt dat vogels in het tweede kleed het vaakst
voorkomen. Het betreffen waarschijnlijk dispergerende
vogels die zich aansluiten bij groepen Vale Gieren tij-
Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
374
dens de trek naar Europa in het voorjaar. Juveniele vor-
men slechts een klein percentage, waarschijnlijk omdat
de meeste nog in het nest zitten op het moment dat de
Vale het Afrikaanse overwinteringsgebied verlaten.
Vervolgens worden de kleden van de drie soorten
beschre ven met de nadruk op de belangrijke deter-
minatie kenmerken: 1 Grootte & bouw: Vale Gier is het
grootst, en het zwaarst gebouwd, met lange rechthoeki-
ge vleugels. Rüppells Gier en Witruggier zijn kleiner,
met meer afgeronde vleugelpunten en een kortere staart;
2 kop: elke soort heeft een opvallende kopvorm.
Rüppells toont erg ‘langsnavelig’, en met een verlengde
kop; Witruggier en Vale hebben een meer driehoekige
kop, die bij Witruggier korter en compacter eruit ziet.
De kleur van de kophuid verschilt ook tussen de drie
soorten, diep rood bij Rüppells, blauwachtig bij Vale en
donker bij Witruggier; laatstgenoemde heeft bovendien
een karakteristiek zwart masker door het ontbreken van
donsveren op de kop waardoor de donkere huid zicht-
baar is; 3 algemeen kleurpatroon: Vale is variabel van
kleur maar doorgaans tamelijk egaal, zonder opvallende
tekening op de onderdelen, terwijl beide Afrikaanse
soorten een opvallend gestreept juveniel kleed hebben,
dat bij Rüppells gevlekt wordt in opeenvolgende rui-
processen. Er is bovendien een subtiel verschil in het
streeppatroon: bij Witruggier eindigen de strepen in een
scherpe punt maar bij Rüppells in een pijlvorm die zich
uitstrekt naar de veerrand (vooral duidelijk op de onder-
staartdekveren en okselveren; 4 grote bovenvleugel-
dekveren (diagnostisch kenmerk): bij Vale met een don-
ker veercentrum en een zandkleurige zoom om de ge-
hele veer, bij Rüppells zwart met een lichte (doorgaans
witte) vlek aan de veertop, en bij Witruggier geheel
egaal en bruinachtig; 5 aantal staartpennen: 14 bij
Rüppells en Vale, 12 bij Witruggier, maar dit kenmerk
moet met enige voorzichtigheid worden gehanteerd
(verlies van veren of actieve rui kunnen gemakkelijk tot
een foute telling leiden).
Ten slotte wordt Rüppells Gier van de Abyssijnse re-
gio in Oost-Afrika besproken (G r erlangeri). Deze on-
dersoort ziet er anders uit dan westelijke vogels, veel
bleker en meer lijkend op Vale Gier. Dergelijke vogels
kunnen in een oostelijke context (bijvoorbeeld Israël)
een determinatieprobleem vormen. De structuurkenmer-
ken en het patroon op de bovenvleugeldekveren zijn
echter vrijwel identiek aan die van nominaat G r ruep-
pelli.
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Identication of Rüppell’s Vulture and White-backed Vulture and vagrancy in the WP
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