Content uploaded by Paweł T. Dolata
Author content
All content in this area was uploaded by Paweł T. Dolata
Content may be subject to copyright.
Food composition and energy demand
of the White Stork Ciconia ciconia
breeding population. Literature survey
and preliminary results from Poland
Jakub Z. Kosicki1, Piotr Profus2, Paweł T. Dolata3& Marcin Tobółka1
1Departament of Behavioural Ecology, Adam Mickiewicz University, Umultowska 89,
61-614 Poznań, Poland, e-mail: kubako@amu.edu.pl
2Institute of Nature Conservation, Polish Academy of Sciences, Mickiewicza 33,
31-512 Kraków, Poland
3South Wielkopolska Group of Polish Society for the Protection of Birds, Wrocławska 60 A/7,
63-400 Ostrów Wielkopolski, Poland
ABSTRACT:This paper presents broad literature survey and preliminary results of study of
food composition of breeding White Stork Ciconia ciconia population from Poland. The field-
work was conducted in the farmland landscapes and river valleys at three areas near Strzelce
Opolskie, Leszno and Ostrów Wiekopolski. During the standard nest visits in the nestling
period we noted prey remains both vomited by chicks as a stress reaction or delivered at nest
by adult birds. The above data on the White Stork’s food composition in the discussed popu-
lations are represented in tables 1–3. Energy value of the food was assessed only for the pop-
ulation from southern Poland. Use of several method of data collection are discussed in the
paper.
KEY WORDS:food, foraging, energy consumption, food examination methods, White Stork,
Ciconia ciconia
Introduction
The quality and quantity of food that parents provide to their chicks is the most im-
portant environmental factor influencing reproduction success of many bird spe-
cies (Martin 1987), including the White Stork Ciconia ciconia (Tryjanowski et al.
2005). Thus the availability of food resources in breeding areas and wintering
grounds is a key factor that regulates survival, number and condition of the White
Tryjanowski P., Sparks T.H. & Jerzak L. (eds.)
The White Stork in Poland: studies in biology, ecology and conservation
Bogucki Wydawnictwo Naukowe, Poznań 2006
Stork population (see Mrugasiewicz 1972, Dallinga & Schoenmakers 1984, 1987,
1989, Profus 1991, 2006a, Struwe & Thomsen 1991, Tryjanowski & Kuźniak 2002,
Schaub et al. 2005, Sæther et al. 2006).
Many hypotheses about the influence of food quantity and quality on White
Storks have not been verified in a credible way. This is because our knowledge
about the stork’s food composition and quality is still limited. In the majority of
papers there are no quantitative analyses of the contribution of particular species
and systematic groups in the food composition, and – what is even more vital – no
assessment of the energy significance of particular components of the White
Stork’s diet has been made (see Bauer & Glutz 1966, Creutz 1985, Làzaro 1986,
Pinowski et al. 1986, 1991, Lakeberg 1995, Struwe & Thomsen 1991, Antczak
et al. 2002).
Habitat changes observed in the past ten years in the agricultural environment
which are unfavourable for storks, for example, the increase of arable monocultures
(e.g. maize Zea mays and rape Brassica napus) at the cost of grassland, excessive mech-
anization and intensification of agriculture, may all account for the diminishing pop-
ulation of the White Stork. Apparently, as a result of such human activities, 16–24%
of stork breeding sites disappeared in the provinces of Silesia and Lubuskie (Jerzak
et al. 2006, Profus 2006b, c, Wuczyński 2006); whereas in other parts of Poland the
size of populations was observed to be stable or increase significantly (Guziak &
Jakubiec 2006). Therefore, research conducted on the composition and quality of
food can contribute to efficient protection of the White Stork species.
Results presented in this paper, both a literature survey and field data, aim at
filling in the gaps in our knowledge about the composition and energy values of the
stork’s food. This paper partially presents data and conclusions contained in
Profus’ (2006a) study, however, it is supplemented by new methods of gaining ma-
terials and field data collected in the region of Wielkopolska.
Methodological assumptions
Methods used in specifying the White Stork diet: a literature review
Stomach analysis and leather cap put on chicks’ beaks
The first attempts to describe diet composition were from stomach content analyses
of storks killed and of those found dead (Rörig 1903, Eckstein 1907, Steinbacher
1936, Stammer 1937, Putzig 1938, Radkiewicz 1984, Nachtigall et al. 1998).
Leather caps put on chicks’ beaks (Fig. 1) so they could not eat food brought to
the nest. The food brought by adult birds to the nest and spat out was collected for
analysis, and after specifying its animal content, returned for the chicks to eat
(Krapivnyj 1957, Körös 1992). For species protection and ethical reasons, both
methods are not used any more.
Direct observation of foraging and feeding birds
Data about the White Stork’s food composition mainly come from direct observa-
tions of foraging birds (Schüz 1940, Pinowski et al. 1986, 1991, Pinowska &
Pinowski 1989, Struwe & Thomsen 1991, Böhning-Gaese 1992, Ranner 1995,
170 Jakub Z. Kosicki, Piotr Profus, Paweł T. Dolata & Marcin Tobółka
Skov 1999), and observations made when chicks were fed (Berndt 1938). Using
this method of specifying food composition, it is necessary to realise its drawbacks.
Among the caught animals, it is easier for the observer to identify more sizeable
prey (moles, rodents, fish, tailless amphibians, reptiles, and leeches) (e.g.
Lakeberg 1995).
Permanent recording by a camera situated close to thenest is a new variation of
direct observation of feeding (Dolata 2006), which makes it possible to identify the
prey better than with the use of a telescope or binoculars, not only thanks to the
proximity to the nest but particularly the view from above into the centre of the
nest (i.e. where the parent spits out food for chicks), which cannot be seen when
observing from the ground.
Analysis of spat-out items
The most frequent method is spat-out item analysis (e.g. Putzig 1935, Drescher
1936, Szijj & Szijj 1955, Schierer 1962, Baudouin 1973, Sackl 1987, Làzaro 1982,
1986, Mužini & Rasajski 1992, Pinowska et al. 1991, Pinowski et al. 1991,
Antczak et al. 2002).
This method allows specifying the biomass of particular animals that were
eaten (e.g. Antczak et al. 2002). However, we need to consider its constraints be-
cause the stork greatly digests vertebrate cartilage and bones (Steinbacher 1936,
Szijj & Szijj 1955, Schulz 1998), which – for this reason – are recorded in the
spat-out bits to a much smaller degree than expected when analysing the stork’s
food. For instance, in Antczak’s et al. studies (2002) bones constituted only 8% of
the pellets, while a hair analysis showed that the remains of voles Microtus sp. only
amounted to 86.5% of the spat-out items. In this situation, identifying prey, i.e.
mammals, through the presence of its hair in the spat out items is a crucial method
(Dziurdzik 1973). Earthworms Lumbricidae poses yet another problem as their
identification must be performed more precisely than in the case of bones, and a
microscope must be used for analysis (Antczak et al. 2002).
Food composition and energy demand of the White Stork breeding population 171
Fig. 1. Schematic drawing leather cap put on chicks’ beak (after Krapivnyj 1957)
Energy value of food; specifying energy demand of individuals
and populations
Specifying caloric demand, being an element of the energy budget of an individual
or the population, is based on a theoretical model which evaluates the assimilated
energy quantity in the period between the arrival and the departure from the
breeding area, as well as the energy that is necessary for the young to grow and be-
come independent. This method, however, has serious constraints because obtain-
ing good results is only possible for birds raised in captivity (e.g. Kushlan 1977,
Keller & Visser 1999).
Specifying the energy value of food
The calorific content of animal food depends mainly on the fat content and not so
much on carbohydrates, proteins or minerals. The energy value of animal fat ex-
ceeds 39 kJ/g of fresh mass (Górecki 1967, Dolnik et al. 1982). The energy value of
other vital elements of the body (proteins and carbohydrates) is nearly half as
much (carbohydrates and animal proteins respectively: 17.58 and 23.66 kJ/g;
Dolnik et al. 1982). So a change in the animal’s fat content is responsible for a sub-
stantial change in the calorific value of the whole body.
There are three methods for calorific value measurements. The first one is the
value obtained directly from burning in the calorimeter, i.e. a top burning value.
also called the dry mass calorie value. The second is obtained from the calorific
value of the dry mass by means of subtracting the ash content, which is the
ash-free calorific value. The third is the biomass calorific value. This value – just
like the previous ones – is reached by taking into account the water content in the
initial sample (Górecki 1967).
Specifying food and energy demand of a breeding pair and a chick:
field methods
Double labelled water (DLW) is an isotope method of testing animal metabolism
(Nagy 1987, Nagy & Obst 1991, Nagy et al. 1999). This technique of establishing
field metabolic rate (FMR) also covers the cost of base metabolic rate (BMR),
thermoregulation and basic life functions. Food-energy needs of birds are deter-
mined by a number of independent factors, but the most important one is the mass
of the body (Nagy & Obst 1991). The energy demand of a breeding stork can be cal-
culated by a general equation:
FMR (kJ/d) = 10.9 M0.64
where M = live body mass of the animal in grams (Nagy 1987, Bozinovic & Medel
1988).
The body mass of breeding storks of both sexes comes from information (recal-
culated) contained in the literature (Sasvári & Hegyi 2001). Field metabolic rates
obtained for an average male and female are respectively: 2136 and 1976 kJ/day, so
for the pair: 4112 kJ. The birds’ daily energy requirement is in fact higher because
the bird is not able to use the entire energy derived from food. Assuming that the
bird derives 75% of the energy from food on average (Bezzel & Prinzinger 1990) –
172 Jakub Z. Kosicki, Piotr Profus, Paweł T. Dolata & Marcin Tobółka
specific data for fish and invertebrates respectively: 77.2% and 73.9% according to
Castro et al. (1989); for fish, amphibians and mammals respectively: 81%, 78%
and 74% (Dolnik et al. 1982) – gross energy disposal for a male amounts to 2847
kJ/day, and the female 2634 kJ/day. So energy requirement of a pair of storks is
5481 kJ/day.
Once we know the daily energy requirement of a pair of storks, it is possible to
calculate the daily food intake (DFI). The amount of food necessary to cover daily
energy requirement may be calculated by dividing DDE by the energy value of 1 g
of food biomass.
In the case of chicks, food and energy demand depends on the individual stage
of development as well as the body mass. Total metabolised energy (TME)
(kJ/chick) is the quantity of energy needed from birth till the bird is able to fly, and
it is proportional to the body mass of a mature individual of the given species
(Drent et al. 1992, Weathers 1996). To calculate total metabolised energy, an equa-
tion published by Weathers (1996) was used:
TME = 6.65 M0.85 ×tfl
0.71
A chick’s energy requirements (gross energy content of food consumed) is also
higher than the field metabolic rate (FMR), because not all the energy in food is
used. Thus it is also necessary to consider the degree to which energy is used from
food. In fact, this is not known for the stork’s chicks, but it is known that young
birds use energy more efficiently than adults, which is well proven, for example, for
owls (e.g. Ceska 1980). The daily maximum energy demand (max. DME) of a
White Stork’s chick can be calculated with the use of an equation by Weathers
(1996):
DME = 11.7 M0.91 × tfl
–0.43
where M is chick mass (in grams), and tfl defines the length of time the chicks re-
main in the nest (in days).
With 85% assimilated food, the value calculated per chick is 3450 kJ. Such en-
ergy is contained in 784 g of food of an average caloric value (4.4 kJ/g of live body
mass). Extreme values are: 3287 kJ for a 2934 gram chick, and 3750 kJ for a 3392
gram chick, which corresponds to a biomass of 747 and 852 g at a food density of
4.4 kJ/g of fresh mass.
The quantity of food that ensures breeding success for a pair of birds
In order to assess food quantity – that a pair of storks must find in the breeding
area to cover their food needs and to raise their offspring – the following conditions
must be fulfilled, according to Profus (2006a):
a) a pair remains in the breeding area for 144 days;
b) average energy value of the food amounts to 4.4 kJ/g of the biomass;
c) a pair of weaker condition (parents of smaller mass and those raising 1–2 off-
spring) consume 1141 g food/day, while strong pairs (parents of bigger mass
with 3–6 offspring) consume on average 1317 g of food a day;
Food composition and energy demand of the White Stork breeding population 173
d) one chick receives 34.3 kg of food from its parents from hatching to the first
flight, and after the first flight (for the next 10 days) the chick gets 3 kg of food,
while it finds 2.5 kg on its own.
From arrival till departure the food demand of parents was assessed at 179.4 kg,
while a pair without young must consume a total of 141.7 kg of food within 130
days. The potential food resources that storks may use have not yet been fully as-
sessed (see Profus 2006a).
Research on the White Stork’s food in Poland
The food composition of the White Stork in Poland has not been studied exten-
sively (see Profus 1985, Ptaszyk 1998).
The first studies on the Polish territory were conducted by German ornitholo-
gists in the area that belonged to Germany at the time. Steinbacher’s work (1936)
was performed on the basis of materials from the then Eastern Prussia (storks
from the present Kaliningrad Region, with only a few samples came from Warmia
and Masuria). Publications by Drescher (1936) and Stammer (1937) concerned
only a part of Silesia (in the past German, now Polish). Scarce information about
the species’ food can also be found in Czudek’s paper (1935) which relates to the
area of Pszczyna and Cieszyn (Silesia).
In later times only Mrugasiewicz (1972) mentions “numerous” observations of
the young spitting out food during a nest check in the valley of the Barycz river
(Milicz district). Between 1959 and 1968 he stated that the main food there was
the Common Frog Rana temporaria and probably the Swamp Frog Rana arvalis.
Quality and quantity of results improved only after studies carried out in 1976
in the Masurian Lakeland in North-Eastern Poland (Pinowski et al. 1986, 1991,
Pinowska & Pinowski 1989, Pinowska et al. 1991), and then in Southern Poland at
the end of the 20th century (Profus 2006a).
The only publication about the food of the non-breeding storks in Poland was
made by Antczak et al. (2002) on the basis of studies in the valley of the Barycz
river in the province of Wielkopolska (SW Poland), where also breeding birds were
observed. The results of the observations have been used in this paper (Table 2).
Field data
Methods of collecting material
Field observations were carried out during the whole breeding season. Most mate-
rial was collected when nests were checked, and dangerous plastic string removed,
as well as material which fell from nests with fledgling, and when ringing the
young in the second half of June and the beginning of July. The composition of the
stork’s food was identified on the basis of animals or their remains found during
nest checks. They were sometimes vomited by the young as a stress reaction to the
checking person (very rare in comparison with the Black Stork Ciconia nigra)(P.T.
Dolata unpubl.). Whole prey or their remains were also collected under nests
where they had fallen when the young had been fed, or they had been thrown out
due to problems with swallowing.
174 Jakub Z. Kosicki, Piotr Profus, Paweł T. Dolata & Marcin Tobółka
Food composition and energy demand of the White Stork breeding population 175
Table 1. Food composition of breeding White Stork population near Strzelce Opolskie
(Southern Poland)
No. of pray Mass (g) %biomass
Fishs Pisces
Brown Trout Salmo trutta m. fario 2 137.5 3.6
Chub Leuciscus cephalus 1 150 3
Gudgeon Gobio gobio 13 104 2.1
Carp Cyprinus carpio 19 845 17
Pike Esox lucius 1 400 8
Crucian Carassius carassius 1 300 6
Stickleback Gasterosteus aculeatus 2 2.5 0.05
Amphibians Amphibia
Fire-bellied Toad Bombina bombina 2 12 0.2
Grass Frog Rana temporaria 3 45 0.9
Edible Frog Rana esculenta 1 32 0.6
Frogs indeterminate Rana sp. 4 160 3.2
Reptails Reptilia
Sand Lizard Lacerta agilis 1 15 0.3
Grass Snake Natrix natrix 2 300 6
Birds Aves
Mallard Anas platyrhynchos (juv.) 1 150 3
White Stork Ciconia ciconia (juv.) 1 100 2
Mammals Mammalia
Mole Talpa europea 9 684 13.8
Common Shrew Sorex araneus 1 9 0.2
Common Vole Microtus arvalis/M. agrestis 22 488 9.8
Water Vole Arvicola terrestris 3 274 5.5
Hare Lepus europaeus (juv.) 2 260 5.2
Mouse Apodemus sp. 1 30 0.6
Invertebrate Invertebrata
Tapeworm Ligula intestinalis 2 2 0.04
Caracoles Planorbis sp. 1
Crayfish Astacus sp. 1
Horse Leech Haemopis sanquisunga 3 8 0.2
Cockchafer M. melolontha 3 2 0.04
Earthworms Lumbricidae several hundreds 455 9.3
Moreover, some data come from visual observations with the use of binoculars.
A supplementary method was to massage the necks of just fed chicks in order to
make them regurgitate their food.
These methods of collecting material, however, have many constraints because
the material obtained was not homogeneous. So the results, except those from
southern Poland, mainly show particular elements of the diet expressed as a per-
centage.
Composition of the White Stork’s food
This paper uses results of research on food from the following regions in Poland:
a) Southern Poland, an area rich in fish ponds near Strzelce Opolskie [50°31'N,
18°18'E] in Opolskie province, Pszczyna [49°58'N, 18°57'E] and Gliwice
[50°17'N, 18°40'E] in Śląskie province (for details see Profus 2006a).
b) An agricultural landscape of western Poland, near Leszno [51°51'N, 16°35'E].
In this area of 810 km2, arable fields are interspersed with meadows, pasture,
human settlements and small woods (for details see Kuźniak 1994). The White
Storks build nests mainly on roofs of buildings, trees and electric poles. During
176 Jakub Z. Kosicki, Piotr Profus, Paweł T. Dolata & Marcin Tobółka
Table 2. Food composition of breeding White Storks near Ostrów Wielkopolski and Jarocin
Fishs Pisces AB
Carp Cyprinus carpio 2
Pike Esox lucius 5
Crucian Carassius carassius 1
Gudgeon/Mullet Gobio gobio 1
Amphibians Amphibia
Green Frogs Rana esculenta complex 4
Common Spadefoot Pelobates fuscus – froglets ca 45
Reptails Reptilia
Grass Snake Natrix natrix 3
Mammals Mammalia
Small indeterminate mammals Mammalia 3
Rodent indeterminate Rodentia 1
Mole Talpa europea 3
Water Vole Arvicola terrestis 1
Invertebrate Invertebrata
Earthworms Lumbricidae several hundreds
Leeches Hirudinea ca. 12
Colorado Beetle Chrysomela decemlineata several items
Bush-cricket Tettigonia viridissima ca. 10
Explanations: A – the food collected under the nest and in nests, B – the food vomit in stress reaction
recent years the number of nests located on poles increased rapidly (Kuźniak
1994).
The Obra river valley, Western Poland [52°07'N; 16°04'E], material collected
from 1997–2000. The study area covers 417 km2, where the proportions of dif-
ferent habitat are: arable field 49%, meadows and pastures 28%, forests 14%,
and 9% inhabited areas, roads, etc. (for further details see Kuźniak 1994).
c) Southern Wielkopolska: 17 sites in the Ostrów Wielkopolski district
[51°30'–51°49'N, 17°31'–18°11'E], and three sites in the Jarocin district
[51°56'–52°06'N, 17°27'–17°38'E]. This area consists of intensive arable land,
and even more extensively farmed valleys of rivers such as the Barycz (with
many fish ponds), the Prosna and the Warta. The following were collected:
three prey (only vertebrates) from three nests, 13 prey (only vertebrates) found
under eight nests, and 11 portions of food (5× vertebrates, 5× invertebrates,
1× both) from eight nests. They were either food spat out by parents for the
young or food vomited by the young during nest checks. The data were gathered
from 1994 to 2005.
Food composition and energy demand of the White Stork breeding population 177
Table 3. Food composition of breeding White Storks near Leszno
Fishs Pisces AB
Bream Abramis brama 2
Crucian Carassius carassius 1
Eel Anguilla anguilla 1
Stickleback Gasterosteus aculeatus 1
Amphibians Amphibia
Grass Frog Rana temporaria 2
Fire-bellied Toad Bombina bombina 1
Reptails Reptilia
Grass Snake Natrix natrix 1
Birds Aves
Pied Wagtail Motacilla alba 1
Skylark Alauda arvensis 2
Mammals Mammalia
Mole Talpa europea 5
Hare Lepus europaeus (juv.) 2
Common Vole and/or Field Vole
Microtus arvalis/M. agrestis
8
Rat Rattus sp. 2
Inwertebrate Invertebrata
Earthworms Lumbricidae several items 1
Explanations – see Table 2
The above data on the White Stork’s food composition in the discussed popula-
tions are represented in Tables 1–3.
The energy value of the food was assessed only for the population from South-
ern Poland. The total weight of storks’ food was estimated at 4975 g (92 verte-
brates and several hundred invertebrates, mainly earthworms). It means that ver-
tebrates amounted to 90.4% of the food’s mass, invertebrates 9.6%. Fish
constituted the main part of food at 39% of the biomass. The biggest item was a
Pike Esox lucius which at about 400 g contained an estimated 1900 kJ of energy.
Smaller fish were also caught, for example, a Three-spined Stickleback Gasterosteus
aculeatus of 1.1 g mass and calorific value of 3.80 kJ/g of the biomass (Massias &
Becker 1990), however the energy value of an individual did not exceed 4.2 kJ. Vital
components of the stork’s diet were small mammals which amounted to 35.1% of
the prey biomass. In this group the most frequently caught animals were voles
Microtus sp. but also Moles Talpa europaea, especially in the areas of high ground wa-
ter level. Apparently, moles are easier to catch in wet areas.
The death of chicks as a result of choking on big prey
Tables 1–3 do not include information gathered from nests from 1994 to 2005
about chicks that choked while eating. In two cases the cause of death was a Mole,
in three cases a Grass Snake Natrix natrix. These data were gathered during studies
in the Ostrzeszów district (1), and mainly from the Ostrów Wielkopolski district
(4). Also, in the same area a Grass Snake (length 80 cm, weight about 200 g) was
found in a alive stork’s oesophagus. It had stuck in such a way that its ribs blocked
the oesophagus. Previously, in Polish literature it was only noted that such big ani-
mals were difficult to swallow (Jakubiec & Szymoński 2000), and, they were not
mentioned as a cause of chicks’ death in Poland (e.g. Jakubiec 1991, Profus &
Chromik 2001). Five cases from a small area suggests that such death is not rare.
Discussion
The only way a bird can obtain energy is by expending metabolic energy while for-
aging for food items that contain appropriate amounts and forms of energy. Birds
must actively pursue, capture, and consume the food that they obtain their energy
from. Furthermore, in order to maintain a positive energy balance and hence suffi-
cient energy available for reproduction, birds must choose among food items that
vary in their energy and nutrient contents (Maurer 1996).
The White Stork is an opportunist as regards its food because it uses resources
that are most easily available, a notion which is proved by observations carried out
at various types of habitat (cf. Pinowski et al. 1991, Profus 2006). Calorific value of
the food shall be also considered as a significant factor. Studies performed in the
Obra river valley showed that there was a strong relationship between the quantity
of potential food, i.e. voles, and the White Stork brood size (Tryjanowski &
Kuźniak 2002). A positive correlation between the brood size and the quantity of
food was also noticed in other areas in Central Europe (Tantzen 1962, Profus &
Mielczarek 1981, Bairlein & Henneberg 2000).
178 Jakub Z. Kosicki, Piotr Profus, Paweł T. Dolata & Marcin Tobółka
Data analysis with respect to collection methods, and a comparison with check
results of spat-out-bits show that prey found under nests or that found uneaten in
nests (e.g. Table 2 A) cannot be reliably treated as the species’ food. Presumably is
because some of the prey were either spat out by storks or too large to be digested.
Fresh prey either brought for the young by parents or vomited by chicks in the nest
as a reaction to stress just before or during a nest check constitutes another group
of material that most probably appears to reflect the real food composition. Inten-
tional provocation of the birds to vomit, for example by giving them an emetic,
could be supplementary to the method. Such a method was used during research
on the Hooded Crow’s Corvus cornix food (Zduniak 2005).
Invertebrates play a really vital role in storks’ food (Pinowska & Pinowski 1989,
Pinowski et al. 1991). They are the basic component of the diet since storks arrive in
the breeding ground. The most frequent groups are predatory Water Beetles
Dytiscidae, Ground Beetles Carabidae, Scarab Beetles Scarabaeidae, Snout Beetles
Curculionidae, and the Orthoptera. Due to the long ontogenetic development of the
Orthoptera, they become the stork’s food in mid June (Pinowski et al. 1991). Another
numerous group of invertebrates in the stork’s diet are earthworms Lumbricidae.
They are the main food component just after arriving from the wintering grounds
(Hornberger 1967). Earthworms are caught throughout the whole season on pas-
tures, meadows, and alfalfa fields, and in late summer during ploughing. Research
carried out in Germany support these findings (Böhning-Gaese 1992).
In the Belorussian part of the Białowieża Forest storks mainly eat various spe-
cies of frogs (Krapivnyj 1957), such as the Common Frog Rana temporaria, the
Swamp Frog Rana arvalis and the Water Frog Rana esculenta complex, which alto-
gether amount to 60.6% of the prey biomass and meet about 53% of the chicks’
food and energy needs. Vertebrates constitute total of 72.5% of the caught bio-
mass, and meet about 64% of the energy demand of the chicks (compare Profus
1986). The remaining 27.5% of the prey biomass is made up of invertebrates, with
the Mole Cricket Gryllotalpa gryllotalpa being the main one. The Diving Beetle’s
larva Dytiscus marginalis (3.5% of the biomass) is a quite frequent item, which along
with remaining insect species amount to 10.4% of the food biomass, and about
14% of the energy the chicks need. Surprisingly, in the diet of storks in this area
there is a low contribution of earthworms at only 1% of the biomass, and a quite
high proportion of leeches (1.1% of the biomass). In July and August the main food
of chick are insects from the Acrididae and Tettigoniidea families (Krapivnyj 1957).
Additionally, studies from North-Eastern Poland (Mazuria) show that among
animals caught by storks invertebrates dominate at 75.3%, while vertebrates con-
stitute 24.7%. In the invertebrate group there are small insects (54.7%), earth-
worms (19.3%), snails Mollusca (0.6%) and big insects (0.7%); and in animals the
vertebrates such as rodents (2.7%), moles (0.15%) and fish (0.2%) (Pinowska &
Pinowski 1989, Pinowski et al. 1991).
Acknowledgments
We thank J. Grześkowiak, P. Tryjanowski, M. Antczak and T.H. Sparks for their
comments on this manuscript. Thank also go to M. Antczak, J. Fijał, T. Ekiert,
Food composition and energy demand of the White Stork breeding population 179
J. Pietrowiak, S. Kuźniak and PwG OTOP members for their help in field work.The
study was supported by UAM grant: PBWB 703/2006.
References
Antczak M., Konwerski S., Grobelny S., Tryjanowski P. 2002. The Food Composition of Im-
mature and Non-breeding White Storks in Poland. Waterbirds 25: 424–428.
Bairlein F., Henneberg R. 2000. Der Weißstorch (Ciconia ciconia) im Oldenburger Land.
Oldenburg. Forsch. N. F. 12: 1–90.
Baudouin G. 1973. Analyse de pelotes de réjection des Cigognes (Ciconia ciconia) nicheuses à
Hachy en 1972. Aves 10: 113-121.
Bauer K., Glutz von Blotzheim U.N. 1966. Handbuch der Vögel Mitteleuropas. Bd. I.
Akademische Verlaggesellschaft, Frankfurt/M.
Berndt R. 1938. Über die Ernährung einer Weissstorchbrut. Beitr. Fortpfl. biol. Vögel 14:
95–98.
Bezzel E., Prinzinger R. 1990. Ornithologie. Ulmer, Stuttgart.
Böhning-Gaese K. 1992. On the feeding ecology of the White Stork (Ciconia ciconia)in
Oberschwaben (Baden-Württemberg, Germany): observations on two pairs. J. Orn. 133:
61–71.
Bozinovic F., Medel R.G. 1988. Body size, energetic and foraging mode of raptors in central
Chile. Oecologia (Berlin) 75: 456–458.
Castro G., Stoyan N., Myers J.P. 1989. Assimilation efficiency in birds: A function of taxon or
food type. Comp. Biochem. Physiol. A 92: 271–278.
Ceska V. 1980. Untersuchungen zu Nahrungsverbrauch. Nahrungsnutzung und
Energiehaushalt bei Eulen. J. Orn. 121: 186–199.
Creutz G. 1985. Der Weißstorch Ciconia ciconia. A. Ziemsen Verlag, Wittenberg Lutherstadt.
Czudek A. 1935. [The White Stork (Ciconia ciconia cic. L.) in Silesian voivodeship]. Wyd.
Muz. Śląskiego w Katowicach. Dział III, 8: 5–44.
Dallinga J.H., Schoenmakers S. 1984. Populatieveranderingen bij de Ooievar Ciconia ciconia
ciconia in de periode 1850–1975. Nederlandse Vereniging tot Bescherming van Vogels,
Zeist.
Dallinga J.H., Schoenmakers S. 1987. Regional decrease in the number of White Storks
(Ciconia c. ciconia) in relation to food resources. Col. Waterbirds 10: 167–177.
Dallinga J.H., Schoenmakers S. 1987. Regional decrease in the number of White Storks
(Ciconia c. ciconia) in relation to food resources. Col. Waterbirds 10: 167–177.
Dolata P.T. 2006. “Close to the Storks” – project of the White Stork’s Ciconia ciconia on-line
nest monitoring, some examples and possibilities of such project’s utility for the scien-
tific researches. In: Tryjanowski P., Sparks T.H., Jerzak L. (eds.) The White Stork in Po-
land: studies in biology, ecology and conservation. Bogucki Wyd. Nauk., Poznań:
437–448.
Dolnik V.R., Dolnik T.V., Postnikov S.N. 1982. [Caloric densities and metabolic efficiency
coefficients of objects eaten by birds]. In: Dolnik V.R. (ed.) Bjudzety vrjemjeni i energii u
ptic v prirodje. AN SSSR. Trudy Zool. Inst. 113: 143–153.
Drescher E. 1936. Storchgewölle aus Schlesien. Ber. Ver. schles. Orn. 21: 8.
Dziurdzik B. 1973. Key to the identification of hairs of mammals from Poland. Acta Zool.
Cracov. 18: 773–791.
Eckstein K. 1907. Die fischereiwirtschaftliche Bedeutung der Vögel. Deuts. Fisch. Ztg 34:
1-45.
180 Jakub Z. Kosicki, Piotr Profus, Paweł T. Dolata & Marcin Tobółka
Górecki A. 1967. Caloric values of the body in small rodents. In: Petrusewicz K. (ed.) Sec-
ondary productivity of terrestrial eceosytems. Polish Academy of Sciences, Kraków:
315–321.
Hornberger F. 1967. Der Weißstorch (Ciconia ciconia). A. Ziemsen Verlag, Wittenberg
Lutherstadt.
Jakubiec Z. 1991. Causes of breeding losses and adult mortality in White Stork Ciconia
ciconia (L.) in Poland. Studia Nat. A 37: 107–124.
Jakubiec Z., Szymoński P. 2000. Bociany i boćki. PTPP “pro Natura”, Wrocław.
Jerzak L., Bocheński M., Czechowski P., Rubacha S. 2006. White Stork in lubuskie province
in 2004. In: Guziak R., Jakubiec Z. (eds.) White Stork Ciconia ciconia (L.) in Poland in
2004. Results of the VIth International White Stork Census. PTPP “pro Natura”,
Wrocław: 93–110.
Keller T., Visser H. 1999. Daily energy expenditure of great cormorants Phalacrocorax carbo
sinensis wintering at Lake Chiemsee, southern Germany. Ardea 87: 61–69.
Kõrös T. 1984. A study of stork foods in large-scale agricultural fields. Puszta 2, 11: 27-38.
Krapivny A. 1957. Nestling food of the White Stork in Bialowieza Primaeval Forest. Vesci
Akad. Nauk BSSR, Ser. Bijal. Navauk 1: 91–98.
Kushlan J.A. 1977. Growth energetics of the White Ibis. Condor 79: 31–36.
Lakeberg H. 1995. Feeding ecology of the White Stork Ciconia ciconia in Oberschwaben
(S-Germany): Feeding area, time budget, development of the young, and territoriality.
Ökol. Vögel 17 (Sonderheft): 1–87.
Lakeberg H. 1995. Feeding ecology of the White Stork Ciconia ciconia in Oberschwaben
(S-Germany): Feeding area, time budget, development of the young, and territoriality.
Ökol. Vögel 17 (Sonderheft): 1–87.
Làzaro E. 1982. Contribución al estudio de la alimentación de la Cigüeńa Blanca en España.
Ed. Univ. Complutense, Madrid.
Làzaro E. 1986. Beitrag zur Ernährungsbiologie des Weißstorchs in Spanien. Beih. Veröff.
Naturschutz Landschaftspflege Bad.-Württ. 43: 235–242.
Martin T.E. 1987. Food as limit on breeding birds: A life-history perspective. Annu. Rev.
Ecol. Syst. 18: 453–487.
Massias A. Becker P. 1990. Nutritive value of food and growth in common tern Sterna hirundo
chicks. Ornis Scand. 21: 187–194.
Maurer B.A. 1996. Energetics of avian foraging. In: Carey C. (ed.). Avian energetics and nu-
tritional ecology. Chapman & Hall, New York: 250–279.
Mrugasiewicz A. 1972. White Stork, Ciconia ciconia (L.) over the district of Milicz in the years
1959–1968. Acta Orn. 13: 243–278.
Mužinic J., Rasajski J. 1992. On food and feeding habits of the White Stork Ciconia c. ciconia,
in the Central Balkans. Ökol. Vögel 14: 211–223.
Nagy K.A. 1987. Field metabolic rate and food requirement scaling in mammals and birds.
Ecol. Monogr. 57: 111–128.
Nagy K.A., Girard I. A., Brown T.K. 1999. Energetics of free-ranging mammals, reptiles, and
birds. Annu. Rev. Nutr. 19: 247-277.
Nagy K.A., Obst B.S. 1991. Body size effects on field energy requirements of birds: what de-
termines their field metabolic rates? Acta XX Contr. Int. Ornitol. Wellington: 793–799.
Pinowska B., Buchholz L., Grobelny S., Stachowiak P., Pinowski J. 1991. Skipjacks Elateridae,
weevils Curculionidae, orthopterans Orthoptera and earwigs Dermaptera in the food of
White Stork Ciconia ciconia from the Mazurian Lakeland. Studia Nat. A 37: 87–106.
Pinowska B., Pinowski J. 1989. Feeding ecology and diet of the White Stork Ciconia ciconia in
Poland. In: Rheinwald G., Ogden J., Schulz H. (eds.) Weißstorch – White Stork. Proc. I
Int. Stork Conserv. Symp. Schriftenreihe des DDA 10, Bonn: 381–396.
Food composition and energy demand of the White Stork breeding population 181
Pinowski J., Pinowska B., de Graaf R., Visser J. 1986. Der Einfluss des Milieus auf die
Nahrungs-Effektivität des Weißstorchs (Ciconia ciconia L.). Beih. Veröff. Naturschutz
Landschaftspflege Bad.-Württ. 43: 243–252.
Pinowski J., Pinowska B., de Graaf R., Visser J., Dziurdzik B. 1991. Influence of feeding habi-
tat on prey capturerate and diet composition of White Stork Ciconia ciconia (L.). Studia
Nat. A 37: 59–85.
Profus P. 1985. Previous research on the White Stork in Poland. Studia Nat. A 28: 9–15.
Profus P. 1986. Zur Brutbiologie und Bioenergetik des Weißstorch in Polen. Beih. Veröff.
Naturschutz. Landschaftspflege Bad.-Wütt. 43: 205–220.
Profus P. 1991. The breeding biology of the White Stork Ciconia ciconia (L.) in the selected
area of Southern Poland. Studia Nat. A 37: 11–57.
Profus P. 1994. Quantitative studies on White Stork Ciconia ciconia – methodological re-
marks. Chrońmy Przyr. Ojcz. 50, 3: 15–33.
Profus P. 2006a. Population changes and breeding ecology of the White Stork Ciconia ciconia
L. in Poland against a background of the European population. Synthesis. Studia Nat. 50:
1–155.
Profus P. 2006b. White Stork in opolskie province in 2004. In: Guziak R., Jakubiec Z. (eds.)
White Stork Ciconia ciconia (L.) in Poland in 2004. Results of the VIth International
White Stork Census. PTPP “pro Natura”, Wrocław: 177–199.
Profus P., Chromik W. 2001. The breeding population of the White Stork Ciconia ciconia (L.)
in Upper Silesia and surrounding areas. I. Present state, numerical changes and breeding
effects in the former districts of Pszczyna and Tychy. Chrońmy Przyr. Ojcz. 57, 6: 28–57.
Profus P., Mielczarek P. 1981. Changes in numbers of White Stork’s Ciconia ciconia (Linnaeus,
1758) in Southern Poland. Acta Zool. Cracov. 25: 139–218.
Ptaszyk J. 1998. What directions should investigations of the Polish White Stork Ciconia
ciconia population follow? Prz. Przyr. 9, 3: 65–76.
Putzig P. 1935. Neue Untersuchungen über die Nahrung des weissen Storches. Deutsche
Jagd. 5, 7: 256–257.
Radkiewicz J. 1984. White stork in the middle Oder river region in 1973–1976. Wyd. WSP,
Zielona Góra.
Ranner A. 1995. Das Raum-Zeit-System der Weissstörche (Ciconia ciconia L.) in Rust
(Burgenland. Österreich): der Einfluss des Nahrungsangebotes auf die Verteilung und
die Bestandsentwicklung der Störche. Dissert. UW, Wien.
Rörig G. 1903. Untersuchungen über die Nahrung unserer heimischen Vögel. Arb. Biol.
Abt. Land- u. Forstw. 4, 1: 51–122.
Sackl P. 1987. Über saisonale und regionale Unterschiede in der Ernährung und
Nahrungswahl des Weißstorches (Ciconia c. ciconia) im Verlauf der Brutperiode. Egretta
30: 49–80.
Sæther B.E., Grøtan V., Tryjanowski P., Barbraud C., Engen S., Fulin M. 2006. Climate and
spatio-temporal variation in the population dynamics of a long distance migrant, the
White Stork. J. Anim. Ecol. 75: 80–90.
Sasvari L., Hegyi Z. 2001. Condition-dependent parental effort and reproductive perfor-
mance in the White Stork Ciconia ciconia. Ardea 89: 281–291.
Schaub M., Kania W., Köppen U. 2005. Variation of primary production during winter in-
duces synchrony in survival rates in migratory White Storks Ciconia ciconia. J. Anim. Ecol.
74: 656–666.
Schierer A. 1962. Sur le régime alimentaire de la Cigogne blanche (Ciconia ciconia) en Alsace.
Premiére contribution: analyse de 24 pelotes de réjection. Oiseau 32: 265–268.
Schulz H. 1998. Ciconia ciconia White Stork. BWP Update 2: 69-105.
Schüz E. 1940. Regenwürmer als Nahrung des Weißen Storchs. Beitr. Fortpflanzungsbiol.
Vögel 16: 203-205.
182 Jakub Z. Kosicki, Piotr Profus, Paweł T. Dolata & Marcin Tobółka
Skov H. 1999. The White Stork (Ciconia ciconia) in Denmark. In: Schulz H. (ed.) White Strok
on the up? Proc. Internat. Symp. White Stork, Hamburg 1996. NABU, Bonn: 111–131.
Stammer H.J. 1937. Ein Beitrag zur Ernährung des Weißen Storches (Ciconia c. ciconia L.).
Ber. Ver. schles. Orn. 22: 20–28.
Steinbacher J. 1936. Untersuchungen über die Nahrungsbiologie des Weißen Storches
(Ciconia ciconia) in Ostpreußen 1933 und 1934. Schrift. Physikal.-Ökonom. Ges.
Königsberg 69: 23–36.
Struwe B., Thomsen K.M. 1991. Studies on the feeding ecology of White Storks (Ciconia
ciconia, L. 1758) at Berenhusen (Schleswig-Holstein, Germany) 1989. Corax 14:
210–238.
Szijj J., Szijj L. 1955. Contributions to the food-biology of the White Stork (Ciconia c. ciconia
L.). Aquila 59–62: 83–94.
Tantzen R. 1962. Der Weiße Storch Ciconia ciconia (L.) im Lande Oldenburg. Oldenburg. Jb.
61: 105–213.
Tryjanowski P., Kuźniak S. 2002. Population size and productivity of the White Stork Ciconia
ciconia in relation to Common Vole Microtus arvalis density. Ardea 90: 213–217.
Tryjanowski P., Sparks T.H., Profus P. 2005. Uphill shifts in the distribution of the White
Stork Ciconia ciconia in southern Poland: the importance of nest quality. Diver. Distrib.
11: 219–223.
Weathers W.W. 1996. Energetics of Postnatal Growth. In: Carey C. (ed.) Avian energetics
and nutritional ecology. Chapman & Hall, New York: 461–496.
Wuczyński A. 2006. White Stork in dolnośląskie province in 2004. In: Guziak R., Jakubiec Z.
(eds.) White Stork Ciconia ciconia (L.) in Poland in 2004. Results of the VIth Interna-
tional White Stork Census. PTPP “pro Natura”, Wrocław: 27-52.
Zduniak P. 2005. Forced regurgitation with tarter emetic as an effective and safe method to
study diet composition in hood crow nestlings. Eur. J. Wildl. Res. 51: 122–125.
Food composition and energy demand of the White Stork breeding population 183
