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255
Research Article
Turk J Zool
34 (2010) 255-266
© TÜBİTAK
doi:10.3906/zoo-0811-22
Clutch and egg size variation, and productivity of the House
Sparrow (Passer domesticus): eects of temperature, rainfall,
and humidity
Aziz ASLAN1,*, Mustafa YAVUZ2
1Akdeniz University, Faculty of Education, Department of Primary Education, 07058 Antalya - TURKEY
2Akdeniz University, Faculty of Arts and Sciences, Department of Biology, 07058 Antalya - TURKEY
Received: 28.11.2008
Abstract: is study was conducted on the campus of the regional department of the forestry service, encompassing
2.25 ha in Antalya city center. e area has gardens and is surrounded by trees, providing nesting and feeding
opportunities for many songbird species. e study aimed to determine clutch and egg size variation, breeding success,
and productivity of the House Sparrow (Passer domesticus), in terms of clutch size and breeding attempts, and to evaluate
variation in temperature, rainfall, and humidity in terms of breeding attempts and years, and their possible eects on given
parameters of the species. In total, 2016 eggs were laid in 393 clutches and clutch size varied from 1 to 11 eggs; the clutches
most commonly contained 4-6 egg in the 3 consecutive years. Mean egg length, width, weight, volume, and sphericity
index were 21.16 ± 0.03 mm, 14.99 ± 0.01 mm, 2.02 ± 0.01 g, 2.38 ± 0.01 cm3, and 71.01 ± 0.09, respectively. Breeding
attempts were aected by temperature (r = 0.97 P < 0.0001) and rainfall (r = −0.84 P < 0.001). Egg length was aected by
rainfall (r = 0.60 P < 0.041), humidity (r = 0.59 P < 0.044), and temperature (r = −0.81 P < 0.002), and egg volume was
aected by temperature (r = −0.68 P < 0.015). is study shows that the House Sparrow population in the study area
exhibited important variation in clutch and egg size, which was aected by changes in temperature, rainfall, and humidity.
Key words: House Sparrow, Passer domesticus, breeding success, clutch size
Ev Serçesi (Passer domesticus)’nin yumurta küme büyüklüğü, yumurta boyutları ve
verimliliği: sıcaklık, yağış ve nemin etkisi
Özet: Çalışma, Antalya’nın şehir merkezinde 2.25 hektarlık araziye sahip olan Orman Bölge Müdürlüğünün bahçesinde
yürütülmüştür. Çalışma alanında bulunan ve ağaçlarla çevrili olan küçük bahçeler, birçok ötücü kuş türüne yuvalanma
ve beslenme olanağı sağlar. Çalışmanın amacı, Ev Serçesi (Passer domesticus)’nin yumurta küme büyüklüğü ve yumurta
boyutlarındaki farklılıkları, üreme başarısını ve verimliliğini, yumurta küme büyüklüğü ve kuluçka dönemlerine bağlı
olarak tespit edilmesi ve ayrıca kuluçka dönemleri ve yıllar baz alınarak sıcaklık, yağış ve nem oranlarındaki değişimlerin
ve bu değişimlerin ilgili parametrelere olası etkilerinin değerlendirilmesidir. Üç yıllık çalışma sonucunda, Ev Serçesinin
393 kuluçkaya 2016 yumurta bıraktığı, yumurta küme büyüklüğünün 1-11 adet yumurta arasında değiştiği ve yaygın
olarak 4-6 yumurtalı kümelerin yapıldığı tespit edilmiştir. Yumurtaların ortalama boy, en, ağırlık, hacim ve küresel indeksi
sırasıyla 21,16 ± 0,03 mm, 14,99 ± 0,01 mm, 2,02 ± 0,01 g, 2.38 ± 0.01 cm3ve 71,01 ± 0,09 olarak hesaplanmıştır. Kuluçka
* E-mail: aaslan@akdeniz.edu.tr
Introduction
Egg size varies greatly among avian populations,
but little within individuals (Christians, 2002). Egg
size varies with laying order, date of laying, and clutch
size (Slagsvold et al., 1984; Järvinen, 1991), and
genetic, ontogenetic, and environmental factors (Potti,
1993). Variation in the size and quality of eggs can
have important long-term consequences for the
survival of offspring (Williams, 1994). Hatchability of
eggs may also be affected by their size (Pinowska et
al., 2002), especially under severe weather conditions
(Järvinen and Väisänen, 1983; Nilsson and Svensson,
1993). For example, larger eggs tend to have higher
hatching success rates (Perrins, 1996), and lead to
larger hatchlings, faster nestling growth (Hipfner and
Gaston, 1999; Pinowska et al., 2004), and more male
offspring (Mead et al., 1987). Experimental studies
have shown that, even though egg size co-varies with
parental quality and age, egg size alone can have
important effects on the quality of nestlings (Bolton,
1991; Smith and Bruun, 1998; Strysky et al., 1999).
Ecological factors, such as food availability,
predator pressure, and weather, are well known to
influence the life history and reproductive success of
a species (Lack, 1968). In the last decade much effort
was expended to investigate the effects of climatic
factors on reproduction, survival, and population
dynamics (Yom-Tov, 2001; Lindström and Kokko,
2002; Laaksonen et al., 2006). Many researchers have
analyzed the effect of ambient temperature on egg size
and reproductive performance in birds (Järvinen and
Ylimaunu, 1986; Järvinen, 1994; Perrins, 1996;
Stevenson and Bryant, 2000; Barkowska et al., 2003;
Saino et al., 2004). The relationship between rainfall
and reproductive performance is thought to be due to
the positive effect of rainfall on food availability for
adults and/or chicks (Boag and Grant, 1984; Zann et
al., 1996). Recently, several studies that tested the
effects of rainfall-related factors on bird breeding
performance were based on testing specific
hypotheses rather than on looking for correlations
(Morrison and Bolger, 2002; Coe and Rotenberry,
2003; Bolger et al., 2005). For example, rainfall could
act as a proximate factor triggering the beginning of
specific physiological processes, such as sex hormone
production or gonad growth (Leitner et al., 2003; Hau
et al., 2004; Fulgione et al., 2005). In comparison to
temperature and rainfall, the influences of humidity
on clutch size, egg size, and other breeding parameters
are less known.
The aims of the present study were to determine
(1) the variation in clutch and egg size, breeding
success, and productivity, (2) the correlations between
egg dimensions, breeding attempts, and clutch size, as
well as between breeding attempts and productivity,
(3) the variation in temperature, rainfall, and
humidity between years and breeding seasons, and (4)
the effects of climatic factors on clutch size, egg size,
breeding success, and productivity of the House
Sparrow for 3 consecutive years.
Materials and methods
This study was conducted from 2001 to 2003 on
the campus of the regional department of the forestry
service covering an area of 2.25 ha located in the city
center (36°53′00′′N, 30°42′00′′E) of Antalya, Turkey
(Figure 1). Sixty-two 14 × 20 × 22-cm wooden nest-
boxes with 1.5-cm thick walls and a 3.5-cm entrance
hole were placed in trees and monitored for 3
breeding seasons. In order to determine the number
of breeding attempts by individual sparrows, 24 adult
females were tagged with a unique combination of 2-
or 3-colored plastic spiral rings in 2003. Nineteen of
the tagged females (79.1%) used the nest-boxes and
the number of breeding attempts did not differ
between tagged and non-tagged females during the 3
years (Aslan et al., 2005). The nest-boxes were
Clutch and egg size variation, and productivity of the House Sparrow (Passer domesticus):
eects of temperature, rainfall, and humidity
256
dönemlerinin sıcaklık (r = 0,97 P < 0,0001) ve yağış (r = −0,84 P < 0,001); yumurta boyunun yağış (r = 0,60 P < 0,041),
nem (r = 0,59 P < 0,044) ve sıcaklık (r = −0,81 P < 0,002); ve yumurta hacminin sıcaklık (r = −0,68 P < 0,015)
değişimlerinden etkilendiği belirlenmiştir. Bu çalışma ile incelenen Ev Serçesi populasyonunun yumurta küme
büyüklüğünün ve yumurta boyutlarının önemli farklılıklar gösterdiği ve bu parametrelerin sıcaklık, yağış ve nemdeki
değişimlerden etkilendiği ortaya konulmuştur.
Anahtar sözcükler: Ev Serçesi, Passer domesticus, üreme başarısı, yumurta küme büyüklüğü
checked twice daily (0800-1000 and 1600-1800) to
determine clutch initiation date, the number of
breeding attempts, egg size (length, width, weight,
volume, and sphericity index), clutch size (number of
eggs in the clutch), and breeding parameters
(unhatched and hatched eggs, dead nestlings, and
fledglings). The exact dates of the onset and
termination of breeding seasons were previously
evaluated in Aslan et al. (2005) and, therefore, the
timing of breeding is not discussed in this report.
Eggs were measured only in completed clutches
and were weighed to the nearest 0.5 g in a plastic bag
with a 5-g Pesola spring scale (accuracy ±0.01 g) in a
plastic tube that kept out wind. Length and width of
each egg were recorded with digital calipers to the
nearest 0.05 mm. We calculated egg volume using
Hoyt’s (1979) equation (V = 0.5 × L × B2), where V is
egg volume (cm3), L is egg length, and B is egg width
(both in mm). The sphericity index was calculated as
100 × B/L (Winkel, 1970). Mean egg size was
calculated by clutch size and by successive breeding
attempts. Values of breeding parameters by breeding
attempt and clutch size allowed us to estimate
breeding success and productivity (Appendix).
Breeding success was estimated for each clutch size
and breeding attempt was estimated with 2 different
methods. With the first method, breeding success was
defined as the number of all successful clutches with
at least 1 fledgling per specific clutch size (BS1 = 100 ×
FL/CS, where FL is the total number of fledglings in
each clutch size and CS is the total number of eggs per
clutch with at least 1 fledgling). With the second
method, breeding success was defined as the number
of clutches with at least 1 fledgling (BS2 = 100 × FL/H,
where H is the total number of eggs hatched with at
least 1 fledgling (Bairlein, 1996; Kiziroğlu, 2008,
2009)). Productivity was calculated for BS1 as 100 ×
H/Htotal and for BS2as 100 × FL/FLtotal for each clutch
A. ASLAN, M. YAVUZ
257
Arboretum
Antalya
TURKEY
0 200 m
N
2.25 ha
Building Green Area Nest
Figure 1. Geographic location of the study area.
size and breeding attempt. Values of climatic factors
(temperature, precipitation, and humidity) were
obtained from the Antalya Meteorological Station,
which is about 5 km from study area, and are
presented in Table 1.
Statistical analysis
Data were analyzed using SPSS v.11.0 for
Windows. Variation in climatic factors between
breeding seasons (from the beginning of April to the
end of July) was determined with ANOVA. Variations
in egg dimensions and breeding parameters for each
clutch size and breeding attempts were determined
using ANOVA, and differences and similarities
between egg dimensions and breeding parameters for
each clutch size and breeding attempts were compared
using Duncan’s multiple comparison analysis. Groups
represented by the same letter are significantly similar
and the others are significantly different. Those
represented by more than 1 letter are similar to groups
represented by the same letter. Furthermore, breeding
success was compared between clutch sizes and
breeding attempts using ANOVA. Correlations
between egg parameters and climatic factors were
determined with Pearson’s correlation test.
Significance was set at P < 0.05 for all statistical tests.
For each test, degrees of freedom (df) and significance
levels are reported. All results are presented as mean
± standard error (SE).
Results
Clutch and egg size
Clutch size varied from 1 to 11 eggs; however, only
2-8 eggs per clutch were found in all years. One-egg
clutches (n = 3 eggs) were abandoned by females and
none of them hatched; therefore, these clutches were
included in the statistical analyses to determine
differences between breeding parameters, but were
excluded from calculations on breeding success and
productivity due to hatching failure. Clutches of 9-11
eggs (n = 60 eggs) were laid by more than 1 female
and were added to the statistical analysis because of
hatching. In total, 153 (38.9%), 121 (30.8%), 91
(23.2%), and 28 (7.1%) clutches were laid in the 1st,
2nd, 3rd, and 4th attempts, respectively (Figure 2).
Most clutches contained 4-6 eggs and the most
common was 5 eggs. Three-year mean clutch size was
5.17 ± 0.07 eggs and differences in mean clutch size
between each breeding attempt were statistically
significant (F3-389 = 20.082, P < 0.0001). Mean clutch
size and numbers decreased from the first 2 to the last
2 attempts (Figure 3).
In all, 1941 (75 eggs could not be measured) eggs
from 378 clutches were measured, and egg length,
width, weight, volume, and sphericity index were
determined as 21.16 ± 0.03 mm, 14.99 ± 0.01 mm,
2.02 ± 0.01 g, 2.38 ± 0.01 cm3, and 71.01 ± 0.09,
Clutch and egg size variation, and productivity of the House Sparrow (Passer domesticus):
eects of temperature, rainfall, and humidity
258
Table 1. Mean monthly temperature, rainfall, and humidity in the study area.
Months
Climatic factors Year
JFMAMJ JASOND
2001 11.4 11.5 15.9 16.8 21.7 25.6 28.5 28.7 25.6 21.0 14.2 11.1
Temperature (°C) 2002 9.1 12.5 14.3 15.9 21.0 26.6 29.3 28.7 24.3 20.6 15.6 10.0
2003 12.7 8.9 11.7 15.8 23.1 26.5 29.7 29.6 24.5 20.8 15.5 11.5
2001 217.7 96.2 9.5 97.3 62.0 - 0.4 - 2.0 16.3 907.2 483.2
Rain (mm) 2002 52.0 22.3 48.8 118.0 9.9 0.1 20.4 1.3 5.5 40.8 68.1 584.4
2003 368.0 122.7 398.8 128.5 84.1 10.5 - - 8.0 21.6 53.8 577.6
2001 67.5 59.8 66.6 67.8 61.0 63.4 69.1 68.6 67.7 55.5 67.9 71.6
Humidity (%) 2002 56.0 63.2 71.3 78.8 73.5 62.7 63.8 63.1 69.9 58.2 65.1 64.3
2003 73.1 51.5 60.3 66.5 57.7 57.3 50.2 54.3 58.1 62.7 61.4 64.9
respectively. The size of eggs differed between
breeding attempts (Table 2); egg length, width,
weight, and volume values for the first 2 attempts
were higher and clearly decreased in the last 2
attempts; in contrast, sphericity index values
increased from the first to last breeding attempt.
Egg dimensions also differed between clutch sizes
(Table 3). Clutch size (r = −0.30, P < 0.0001), and
egg length (r = −0.20, P < 0.0001), width (r = −0.12,
P < 0.0001), weight (r = −0.08, P < 0.0001), and
volume (r = −0.20, P < 0.0001) were negatively
correlated with breeding attempt, while the
sphericity index was positively correlated with
breeding attempt (r = 0.12, P < 0.0001). Moreover,
egg length (r = 0.07, P < 0.003), width (r = 0.09, P
< 0.0001), and volume (r = 0.10, P < 0.0001) were
positively correlated with clutch size.
Differences in temperature and rainfall between
years were not statistically significant (P > 0.05),
whereas differences in humidity were significant (F3-
12 = 4.517, P < 0.024). Differences in temperature and
rainfall between breeding attempts were statistically
significant (temperature: F3-12 = 159.121, P < 0.0001;
rainfall: F3-12 = 14.338, P < 0.0001), while no differences
in humidity were observed (P > 0.05). The number of
breeding attempts was positively correlated with
temperature (r = 0.97, P < 0.0001), but negatively
correlated with rainfall (r = −0.84, P < 0.001). Egg
length was positively correlated with rainfall (r = 0.60,
P < 0.041) and humidity (r = 0.59, P<0.044), while it
was negatively correlated with temperature (r = −0.81,
P < 0.002). Furthermore, there was a negative
correlation (r = −0.68, P < 0.015) between temperature
and egg volume.
A. ASLAN, M. YAVUZ
259
60
50
40
30
20
10
0
1st
2nd
3rd
4th
Number of cluthes
1 2 3 4 5 6 7 8 9 10 11
Clutch Size
Figure 2. Frequency distribution of clutch size based on breeding
attempts.
6.5
6.0
5.5
5.0
4.5
4.0
3.5
3.0
2.5
Mean clutch size
1 2 3 4
Breeding attempts
cc
b
a
Figure 3. Mean clutch size of breeding attempts (letters denoting
differences are given below the error bars).
Table 2. Differences and similarities in egg size between breeding attempts.
Breeding Attempts
Egg sizes ANOVA
1st 2nd 3rd 4th
Length 21.33 ± 0.04 c 21.24 ± 0.04 c 20.85 ± 0.06 b 20.48 ± 0.11 a F3-1937: 30.58, P < 0.0001
Width 15.00 ± 0.02 c 15.08 ± 0.02 c 14.87 ± 0.03 b 14.73 ± 0.05 a F3-1937: 20.15, P < 0.0001
Weight 2.03 ± 0.01 bc 2.04 ± 0.01 c 1.99 ± 0.02 b 1.92 ± 0.03 a F3-1937: 8.04, P < 0.0001
Volume 2.41 ± 0.01 c 2.42 ± 0.01 c 2.31 ± 0.01 b 2.23 ± 0.02 a F3-1937: 37.79, P < 0.0001
Sph. Index 70.48 ± 0.13 a 71.15 ± 0.17 ab 71.53 ± 0.21 bc 72.11 ± 0.45 c F3-1937: 9.37, P < 0.0001
n 788 634 423 96
n: Total number of eggs measured.
Breeding success and productivity
When data for the 3-year period were pooled, the
mean number of unhatched, hatched, dead nestlings,
and fledglings per clutch was 2.28 ± 0.09, 2.85 ± 0.09,
1.05 ± 0.06, and 1.80 ± 0.07, respectively, and differed
between clutch sizes (Table 4). Analysis showed that
5-egg clutches and the first breeding attempt were the
most productive.
Clutch and egg size variation, and productivity of the House Sparrow (Passer domesticus):
eects of temperature, rainfall, and humidity
260
Table 3. Egg size according to clutch size.
Clutch size n Length (mm) Width (mm) Weight (g) Sphericity index Volume (cm3)
1 3 20.74 ± 0.27 ab 14.87 ± 0.10 ab 2.09 ± 0.08 b 71.72 ± 0.81 ab 2.30 ± 0.05 a
2 14 20.65 ± 0.30 ab 14.82 ± 0.18 a 2.02 ± 0.05 b 71.95 ± 1.38 ab 2.27 ± 0.06 a
3 63 20.98 ± 0.16 ab 14.86 ± 0.09 ab 1.98 ± 0.05 b 71.01 ± 0.55 ab 2.33 ± 0.04 ab
4 324 20.85 ± 0.07 ab 14.90 ± 0.03 ab 2.00 ± 0.01 b 71.67 ± 0.23 ab 2.32 ± 0.01 ab
5 625 21.29 ± 0.05 bc 14.99 ± 0.02 ab 2.01 ± 0.01 b 70.58 ± 0.16 ab 2.39 ± 0.01 ab
6 588 21.22 ± 0.04 abc 15.03 ± 0.02 ab 2.06 ± 0.01 b 70.97 ± 0.16 ab 2.40 ± 0.01 ab
7 224 21.11 ± 0.07 abc 14.97 ± 0.04 ab 2.01 ± 0.02 b 71.11 ± 0.30 ab 2.37 ± 0.01 ab
8 40 21.24 ± 0.18 bc 15.20 ± 0.08 bc 1.95 ± 0.02 b 71.73 ± 0.49 ab 2.46 ± 0.04 bc
9 18 21.30 ± 0.17 bc 14.78 ± 0.12 a 1.98 ± 0.02 b 69.51 ± 0.96 a 2.33 ± 0.03 ab
10 20 20.52 ± 0.24 a 14.92 ± 0.09 ab 1.59 ± 0.08 a 72.97 ± 1.19 b 2.28 ± 0.02 a
11 22 21.77 ± 0.19 c 15.36 ± 0.07 c 2.32 ± 0.07 c 70.63 ± 0.44 ab 2.57 ± 0.04 c
Total 1941 21.16 ± 0.03 14.99 ± 0.01 2.02 ± 0.01 71.01 ± 0.09 2.38 ± 0.01
ANOVA F10-1930=27.38, F10-1930=3.83, F10-1930=10.74, F10-1930=2.52, F10-1930=6.41,
P < 0.0001 P < 0.0001 P < 0.0001 P < 0.005 P < 0.0001
n: Total number of eggs measured for each clutch size.
Table 4. Breeding parameters according to clutch size.
Clutch size n Unhatched eggs Hatched eggs Dead nestlings Fledglings
1 3 1.00 ± 0.00 a 0.00 a 0.00 a 0.00 a
2 7 1.43 ± 0.20 ab 0.57 ± 0.20 ab 0.00 ± 0.00 a 0.57 ± 0.20 ab
3 21 1.45 ± 0.26 ab 1.55 ± 0.26 abc 0.41 ± 0.17 ab 1.14 ± 0.22 ab
4 86 1.66 ± 0.15 ab 2.34 ± 0.15 abcd 0.86 ± 0.12 abc 1.48 ± 0.13 abc
5 130 2.24 ± 0.14 ab 2.76 ± 0.14 bcde 0.95 ± 0.11 abc 1.81 ± 0.12 abc
6 103 2.67 ± 0.19 ab 3.33 ± 0.19 cdef 1.30 ± 0.14 abc 2.03 ± 0.16 abc
7 32 2.72 ± 0.35 ab 4.28 ± 0.35 def 1.69 ± 0.24 abc 2.59 ± 0.27 bc
8 5 3.00 ± 0.00 ab 5.00 ± 0.00 ef 2.60 ± 0.51 c 2.40 ± 0.51 bc
9 2 3.50 ± 0.50 b 5.50 ± 0.50 f 2.00 ± 1.00 bc 3.50 ± 0.50 c
10 2 8.00 ± 2.00 c 2.00 ± 2.00 abcd 0.50 ± 0.50 ab 1.50 ± 1.50 abc
11 2 8.50 ± 2.50 c 2.50 ± 2.50 bcd 0.00 ± 0.00 a 2.50 ± 2.50 bc
Total 393 2.28 ± 0.09 2.85 ± 0.09 1.05 ± 0.06 1.80 ± 0.07
ANOVA F10-382 = 8.96, F10-382 = 8.20, F10-382 = 4.08, F10-382 = 3.72,
P < 0.0001 P < 0.0001 P < 0.0001 P < 0.0001
n: Total number of each clutch size.
There were no significant differences between the
breeding success of clutch sizes and breeding
attempts, according to ANOVA (BS1: F7-378 = 1.99, P >
0.436 and BS2: F7-306 = 1.42, P > 0.198) (Figure 4A-D).
In contrast, BS2(Figure 4 B) for clutch size, and BS1
and BS2for breeding attempts differed according to
Duncan’s test (Figure 4C-D). In addition, clutch size
correlated with BS1 (r = −0.17, P < 0.005) and BS2(r =
A. ASLAN, M. YAVUZ
261
70
60
50
40
30
20
60
55
50
45
40
80
75
70
65
60
55
110
100
90
80
70
60
50
40
30
123 4
01 2 34
567 118910
Clutch Size
Bs1 (%)Bs2 (%)
Bs2 (%)
Bs1 (%)
123 4 56 7 118910
Clutch Size
Number of breeding attempts
01234
Number of breeding attempts
A
B
CD
34.2
20.1
6.4
Figure 4. Breeding success and productivity according to clutch size (A and B) and breeding attempts (C and D) (productivity of each
clutch size and breeding attempt as a percentage, and letters denoting differences in breeding success are given above and
below the error bars).
−0.18, P < 0.003), but no relationships were observed
between breeding success and breeding attempts.
Productivity of breeding attempts clearly decreased
from the 1st to 4th attempts (r = −0.988, P < 0.0001 for
BS1and r = −0.981, P < 0.0001 for BS2).
Discussion
In the House Sparrow, clutch size usually ranges
from 2 to 7 eggs (Haartmann, 1969; Balat, 1974). In
Iraq and Israel, clutch size varies from 2 to 7 and from
3 to 7 eggs, and the modal clutch size and most
successful clutch size is 5 and 6 eggs per clutch,
respectively (Al-Dabbagh and Jiad, 1988; Singer and
Yom-Tov, 1988). In contrast, Seel (1968) reported that
clutches of 4 eggs are the most common and the most
successful in England. According to Erdoğan and
Kiziroğlu (1995), and Sıkı (1992), clutch size in
Turkey ranges from 3-6 and 3-7 eggs, respectively, and
the most common and most successful clutch size was
5 eggs per clutch. In the present study, clutch size
ranged from 1 to 11 eggs and clutches of 4-6 eggs were
common. The most common and most successful
clutch size was 5 eggs. These results support Murphy’s
claim (1978) that females lay fewer eggs than their
maximum reproductive capacity allows. Jones and
Ward (1976) also suggested that females inherit the
ability to vary clutch size within a certain range and
that the upper limit of clutch size is firmly fixed.
Nonetheless, as reported by Charnov and Krebs
(1974), there might be a trade-off between a female’s
longevity and her level of reproduction in a particular
time. Seasonal variation in clutch size has been
reported by Seel (1968) and Murphy (1978), as clutch
size is variable between breeding attempts. The
differences in seasonal clutch size observed in the
present study seem to support this variation. We
observed that mean clutch size was the highest in the
first 2 breeding attempts, and decreased slightly with
the 3rd and 4th breeding attempts. Lack (1966)
reported that seasonal changes in clutch size can be
adaptive; larger clutches should be laid when
conditions for raising young are most suitable. Our
results support this hypothesis, as the first 2 clutches,
which were larger, occurred when conditions in the
study area were suitable. A decrease in food supplies
and variation in climatic conditions result in a
decrease in breeding performance (Lack, 1968). The
seasonal variation in food supplies during the
breeding period in the study area is also thought to be
the reason for clutch and egg size differences between
breeding attempts.
For several bird species temperature close to the
upper critical level could have a negative effect on egg
size (Lorenz and Almquist, 1936; Kendeigh, 1941;
Mueller, 1961; Clark and Amin, 1965). In the present
study, 1st and 2nd breeding attempts with larger
corresponding clutches were recorded in April and
May, whereas the 3rd and 4th breeding attempts with
smaller clutches were recorded in June and July (Aslan
et al., 2005). Mean temperature during these months
ranged from 16.2 °C in May to 29.2 °C July (Table 1).
This suggests that the more suitable temperatures
ranged from 16 to 22°C, and that higher temperatures
had negative effects on both clutch size and egg size.
Productivity of the studied population also declined
as temperature increased. It was observed that an
increase in temperature resulted in an increase in the
number of breeding attempts; however, temperature
had a negative effect on clutch size and, consequently,
clutch size and egg size decreased from the first to last
2 breeding attempts. In contrast, rainfall had a positive
effect on the number of breeding attempts. In
addition, egg length was positively affected, not only
by rainfall, but also by an increase in humidity.
Rainfall rates, as opposed to humidity, during the
breeding period were significantly different and
clearly decreased from April to August.
It was reported that the production of eggs by
passerines is energetically expensive (Ricklefs, 1974;
Murphy, 1978; Pinowska, 1979; Järvinen and
Väisanen, 1984), but others reported that it is not
(Krementz and Ankney, 1986; Ward, 1996). There was
a positive correlation between clutch size and egg size
in the present study, suggesting that larger clutches
contain larger eggs, which must require much more
energy and should be expensive for the females.
Lack’s hypothesis (1954, 1966) implies that the
modal clutch size is more productive than other clutch
sizes, whereas Klomp (1970), and Jones and Ward
(1976) argued that birds are capable of laying clutches
that vary in size and a modal clutch size can be smaller
than the most productive one. The negative
correlation between clutch size and breeding success
observed in the present study supports Lack’s
Clutch and egg size variation, and productivity of the House Sparrow (Passer domesticus):
eects of temperature, rainfall, and humidity
262
hypothesis (1954, 1966) that larger clutch sizes are not
necessarily associated with improved breeding success
and that modal clutch size is more important for
breeding success. Clutch size, the number of
unhatched eggs, hatched eggs, dead nestlings, and
fledglings are the most important patterns for
determining breeding success and productivity in
birds (Deckert, 1969; Kiziroğlu, 1981).In the present
study, means of breeding parameters based on clutch
size were significantly different, whereas no
differences were observed between breeding successes
using ANOVA. Nonetheless, Duncan’s test results did
show significant differences between BS2. Despite
differences in breeding patterns, the effect of climatic
conditions, decreases in food supplies, and reduced
breeding desire of females during the breeding period,
no differences were observed between the breeding
successes of breeding attempts by ANOVA, but
according to Duncan’s test results, the differences were
significant. Clutches of 4-6 eggs were the most
productive and productivity of the breeding attempts
decreased from the first to the last breeding attempt
during the breeding season. These results show that
the House Sparrow had consistent breeding success
and productivity during the breeding season in the
study area.
In conclusion, the results obtained in the present
study and our previous work (Aslan et al., 2005) show
that nesting House Sparrows have a flexible response
to changes in environmental conditions. Overall,
temperature and rainfall had a greater effect on clutch
size, egg size, and reproductive performance than did
humidity. It is thought that data from this study and
our previous study could provide a basis for
monitoring future changes and to test specific
hypotheses concerning the breeding ecology of the
House Sparrow in the study area.
Acknowledgements
This study was supported by the Scientific
Research Projects Unit of Akdeniz University. We
thank D. Summers-Smith and J. Pinowski for their
valuable comments on the draft manuscript. We also
wish to thank the numerous students that helped
collect data during the study.
A. ASLAN, M. YAVUZ
263
Al-Dabbagh, K.Y. and Jiad, J.H. 1988. The breeding biology of the
House Sparrow in central Iraq. Intern. Stud. Sparrows 15: 22-43.
Aslan, A., Yavuz M. and Erdoğan, A. 2005. A comparative study of
the breeding ecology of the House Sparrow (Passer domesticus
L.): timing of breeding and breeding success. Isr. J. Zool. 51:
361-380.
Bairlein, F. 1996. Ökologie der Vögel. Fischer, Stuttgart
Balat, F. 1974. Gelegegrosse und Brutverlust des Haussperlings, Passer
domesticus L. İn Mittelmahren. Zool. Listy. 23: 229-240.
Barkowska, M., Pinowski, J. and Pinowska, B. 2003. The effect of
trends in ambient temperature on egg volume in the tree
sparrow Passer montanus. Acta Ornithol. 38: 5-13.
Boag, P.T. and Grant, P.R. 1984. Darwin’s finches (Geospiza) on Isla
Daphne Major, Galapagos: breeding and feeding ecology in a
climatically variable environment. Ecol. Monogr. 54: 463-489.
Bolger, D.T., Patten, M.A. and Bostock, D.C. 2005. Avian reproductive
failure in response to an extreme climatic event. Oecologia 142:
398-406.
Bolton, M. 1991. Determinants of chick survival in the lesser black-
backed gull: relative contributions of egg size and parental
quality. J. Anim. Ecol. 60: 949-960.
Charnov, E.L. and Krebs, J.R. 1974. On clutch size and fitness. Ibis
116: 217-219.
Christians, J.K. 2002. Avian egg size: variation within species and
inflexibility within individuals. Biol. Rev. 77: 1-26.
Clark, C.E. and Amin, M. 1965. The adaptability of chickens to
various temperatures. Poultry Sci. 44: 1003-1009.
Coe, S.J. and Rotenberry, J.T. 2003. Water availability affects clutch
size in a desert sparrow. Ecology 84: 3240-3249.
Deckert, G. 1969. Zur Ethologie und Okologie des Haussperlings.
Beitr. Vogelk. 15:1-84.
Erdoğan, A. and Kiziroğlu, İ. 1995. Brutbiologische Untersuchungen
am Feld-Passer montanus und P. domesticus in Beytepe/Ankara.
Orn. Verh. 25: 211-218.
References
Clutch and egg size variation, and productivity of the House Sparrow (Passer domesticus):
eects of temperature, rainfall, and humidity
264
Fulgione, D., Rippa, D., Caliendo, M.F. and Milone, M. 2005. Seasonal
Breeding In The Italian Sparrow: Plasma Androgen Levels And
Spermatogenesis. Isr. J. Zool. 51: 229-240.
Haartmann, L.V. 1969. The Nesting Habits of Finnish Birds I.
Passeriformes. Commentationes Biologicae Societal
Scientiarum Fennica 32: 1-187.
Hau, M., Wikelski, M., Gwinner, H. and Gwinner, E. 2004. Timing of
reproduction in a Darwin’s finch: temporal opportunism under
spatial constraints. Oikos 106: 489-500.
Hipfner, J.M. and Gaston, A.J. 1999. The relationship between egg size
and post-hatching development in the thick-billed murre.
Ecology 80: 1289-1297.
Hoyt, D.F. 1979. Practical methods for estimating volume and fresh
weight of bird eggs. Auk 96: 73-77.
Järvinen, A. and Väisänen, R.A. 1983. Egg size and related
reproductive traits in a southern passerine Ficedula hypoleuca
breeding in an extreme northern environment. Ornis Scand. 14:
253-262.
Järvinen, A. and Väisänen, R.A. 1984. Reproduction of Pied
Flycatchers (Ficedula hypoleuca) in good and bad breeding
seasons in a northern marginal area. Auk 101: 439-450.
Järvinen, A. 1991. Proximate factors affecting egg mass in subarctic
hole-nesting passerines. Ornis Fenn. 68: 99-104.
Järvinen, A. 1994. Global warming and egg size of birds. Ecography
17: 108-110.
Järvinen, A. and Yliamunu, Y. 1986. Intraclutch egg-size variation in
birds: physiological responses of individuals to fluctuations of
environmental conditions. Auk 103: 235-237.
Jones, D.J. and Ward, P. 1976. The level of reserve protein as the
proximate factor controlling the timing of breeding and clutch
size in the Red-billed Quelea quelea. Ibis 118: 547-573.
Kendeigh, S.C. 1941. Length of day and energy requirements for
gonad development and egg laying. Ecology 22: 237-248.
Kiziroğlu, İ. 1981. Ankara Beynam Ormanı’ndaki baştankara, Parus
L., cinsi (Aves) türlerinin biyoloji, ekoloji ve davranışları ile ilgili
araştırmalar. TÜBİTAK, TBAG-371, 216 pp.
Kiziroğlu, İ. 2008. Türkiye Kuşları Kırmnızı Listesi. Red Data Book
of the Turkish Birds. Ankamat Mar., Ankara, 168 pp.
Kiziroğlu, İ. 2009. Kürkiye Kuşları Cep Kitabı. The Pocketbook of the
Turkish birds. (in press).
Klomp, H. 1970. The determination of clutch size in birds. Ardea 58:
1-24.
Krementz, D.G. and Ankney, C.D. 1986. Bioenergetics of egg
production by female the House Sparrows. Auk 103: 299-305.
Laaksonen, T., Ahola, M., Eeva, T., Väisänen, R.A. and Lehikoinen,
E. 2006. Climate change, migratory connectivity and changes
in laying date and clutch size of the pied flycatcher. Oikos 114:
277-290.
Lack, D. 1954. The natural regulation of animal numbers. Oxford:
Clarendon Press.
Lack, D. 1966. Population studies of birds. Oxford: Clarendon Press.
Lack, D. 1968. Ecological adaptations for breeding in birds. Chapman
and Hall, London.
Leitner, S., Van’t Hof, T.J. and Gahr, M. 2003. Flexible reproduction in
wild canariesis independent of photoperiod. Gen. Compar.
Endocrinol. 130: 102-108.
Lindström, J. and Kokko, H. 2002. Cohort effects and population
dynamics. Ecol. Lett. 5: 338-344.
Lorenz, F.W. and Almquist, H.J. 1936. Seasonal variations in egg
quality. Poultry Sci. 15: 14-18.
Mead, P.S., Morton, M.L. and Fish, B.E. 1987. Sexual dimorphism in
egg size and implications regarding facultative manipulation of
sex in Mountain White-Crowned Sparrows. Condor, 89/4: 798-
803.
Morrison, S.A. and Bolger, D.T. 2002. Variation in a sparrow’s
reproductive success with rainfall: food and predator-mediated
processes. Oecologia 133: 315-324.
Mueller, W.J. 1961. The effect of constant and fluctuating
environmental temperatures on the biological performance of
laying pullets. Poultry Sci. 40: 1562-1571.
Murphy, E.C. 1978. Seasonal variation in reproductive output of the
House Sparrow: The determination of clutch size. Ecology 59:
1189-1199.
Nilsson, J.A. and Svensson, E. 1993. Causes and consequences of egg
mass variation between and within blue tit clutches. J. Zool.
Lond. 230: 469-481.
Perrins, C.M. 1996. Eggs, egg formation and the timing of breeding.
Ibis 138 (supplement): 2-15.
Pinowska, B. 1979. The effect of energy and building resources of
females on the production of the House Sparrow (Passer
domesticus L.) populations. Ekol. Pol. 27: 363-396.
Pinowska, B., Barkowska, M., Pinowski, J., Bartha, A., Hahm, K.H.
and Lebedeva, N. 2002. Influence of temperature on Tree
Sparrow Passer montanus egg mass according to laying
sequence. Intern. Stud. Sparrows 29: 33-47
Pinowska, B., Barkowska, M., Pinowski, J., Bartha, A., Hahm, K.H.
and Lebedeva, N. 2004. The effect of egg size on growth and
survival of the Tree Sparrow Passer montanus nestlings. Acta
Ornithol. 39: 121-135.
Potti, J. 1993. Environmental, ontogenetic and genetic variation in egg
size of Pied Flycatchers. Can. J. Zool. 71: 1534-1542.
Ricklefs, R.E. 1974. Energetics of reproduction in birds. In: Paynter
RA Avian Energetics. Nuttall Ornithological Club, Cambridge,
Massachusetts, pp 152-292.
Saino, N., Romano, M., Ambrosini, R., Ferrari, R.P. and Moller, A.P.
2004. Timing of reproduction and egg quality covary with
temperature in the insectivorous Barn Swallow, Hirundo rustica.
Functional Ecology 18: 50-57.
A. ASLAN, M. YAVUZ
265
Seel, D.C. 1968. Clutch size, incubation and hatching success in the
House Sparrow and tree sparrow Passer spp. at Oxford. Ibis 110:
270-282.
Sıkı, M. 1992. Ev Serçesi (Passer domesticus)’nin üreme biyolojisi
üzerine araştırmalar. Doğa – Tr. J. of Zoology 16: 243-247.
Singer, R. and Yom-Tov, Y. 1988. The breeding biology of the House
Sparrow Passer domesticus in Israel. Ornis Scand. 19: 139-144.
Slagsvold, T., Sandvik, J., Rofstad, G., Lorentsen, Ö. and Husby, M.
1984. On the adaptive value of intraclutch egg size variation in
birds. Auk 101: 685-697.
Smith, H.G. and Bruun, M. 1998. The effect of egg size and habitat
on starling nestling growth and survival. Oecologia 115: 59-63.
Stevenson, I.R. and Bryant, D.M. 2000. Climate change and
constraints on breeding. Nature 406: 366-367.
Strysky, J.D., Eckerle, K.P. and Thompson, C.F. 1999. Fitness-related
consequences of egg mass in nestling house wrens. Proc. R. Soc.
B 266: 1253-1258.
Ward, S. 1996. Energy expenditure of female Barn Swallows Hirundo
rustica during egg formation. Physiol. Zool. 69: 930-951.
Williams, T.D. 1994. Intraspecific variation in egg size and egg
composition in birds: effect of offspring fitness. Biol. Rev. 68:
35-39.
Winkel, W. 1970. Hinweise zur Art und Altersbestimmung von
nestlingen, Höhlenbrüten der Vogelarten anhand ihrer
körperentwicklung. Vogelwelt 91: 52-59.
Yom-Tov, Y. 2001. Global warming and body mass decline in Israeli
passerine birds. Proc. R. Soc. Lond. B 268: 947-952.
Zann, R.A., Morton, S.R., Jones, K.R. and Burley, N.T. 1996. The
timing of breeding by zebra finches in relation to rainfall in
central Australia. Emu 95: 208-222.
Clutch and egg size variation, and productivity of the House Sparrow (Passer domesticus):
eects of temperature, rainfall, and humidity
266
Appendix. Breeding parameter values according to breeding attempt, clutch size, and year.
Breeding Clutch n *n Unhatched Hatched Dead Fledglings
attempts size eggs eggs nestlings
I2122---
3515 7 8 1 7
42392 37 5525 30
5 57 285 140 145 56 89
6 48 288 142 146 49 97
71391 28 6324 39
8 2 16 6 10 5 5
919 4 5 1 4
10 1 10 6 4 1 3
11 2 22 17 5 - 5
Total 153 830 389 441 162 279
II 2 1 2 1 1 - 1
339 6 3 2 1
42288 43 4517 28
5 35 175 65 110 31 79
6 41 246 99 147 64 83
7 16 112 45 67 27 40
818 3 5 4 1
919 3 6 3 3
10 1 10 10 - - -
Total 121 659 275 384 148 236
III 1 2 2 2 - - -
248 6 2 - 2
3 7 21 14 7 1 6
4 29 116 47 69 22 47
5 30 150 70 80 28 52
61484 34 5021 29
7 3 21 14 7 3 4
8 2 16 6 10 4 6
Total 91 418 193 225 79 146
IV 1 1 1 1 - - -
212 1 1 - 1
3 6 18 5 13 2 11
41248 18 30 9 21
5 8 40 12 28 13 15
Total 28 109 37 72 24 48
Total 1 3 3 3 - - -
2 7 14 10 4 - 4
32163 29 34 9 25
4 86 344 145 199 73 126
5 130 650 290 360 125 235
6 103 618 275 343 134 209
7 32 224 87 137 54 83
8 5 40 15 25 13 12
9 2 18 7 11 4 7
10 2 20 16 4 1 3
11 2 22 17 5 - 5
Total 393 2016 894 1122 413 709
n: Total number of each clutch size; *n: total number of eggs for each clutch size.