BREEDING PARAMETERS OF PASSER HISPANIOLENSIS IN SOUTHERN PORTUGAL

2. Some ecological considerations

2.1. Breeding parameters of Spanish sparrow Passer hispaniolensis in southern Portugal

Título:

Parâmetros reprodutores de Pardal-espanhol Passer hispaniolensis no sul de Portugal

Autor:

Paulo A. M. Marques

Revista:

International Studies on Sparrows, 2002 volume 29: 11-20.

Editada pelo Institute of Ecology da Polish Academy of Sciences e pelo working group on granivorous birds da International Association for Ecology.

Resumo: Este é o primeiro estudo da biologia de reprodução de Pardalespanhol Passer hispaniolensis em Portugal e o segundo na Europa ocidental. Este estudo teve como objectivo determinar os principais parâmetros reprodutores para a população que ocorre no sul de Portugal assim como o estudo da sua variação ao longo da época reprodutora e entre os diferentes anos. Sete colónias e 339 ninhos foram estudados durante três anos (de 1999 a 2001) no sul de Portugal. A época reprodutora decorreu desde o fim de Março, princípios de Abril, até meados de Julho, tendo os indivíduos tempo para duas tentativas de reprodução por ano. O tamanho de postura foi de 4.90±0.04, sendo semelhante ao observado por outros autores.

O sucesso de eclosão foi de 67.14%, o sucesso das crias foi de 47.39% e o sucesso reprodutor de 31.98%. Os ninhos com sucesso produziram, em média, 2.77±0.07 juvenis voadores. Estes valores são inferiores aos descritos para o Norte de África e para as populações orientais. Aproximadamente 55% dos ninhos produziram pelo menos um juvenil voador. A variabilidade intra e inter-anual detectada neste estudo sugere a existência de grandes variações nas condições ambientais que condicionam o sucesso reprodutor da espécie. O elevado grau de sincronia reprodutora e a relativa curta duração do ciclo reprodutor, associados ao comportamento gregário e nómada da espécie, potenciam a capacidade do Pardal-espanhol de aproveitar condições favoráveis para a reprodução de curta duração (características de alguns dos habitats onde a espécie ocorre).

BREEDING PARAMETERS OF SPANISH SPARROW PASSER HISPANIOLENSIS IN SOUTHERN PORTUGAL

Paulo A. M. MARQUES Centro de Biologia Ambiental /D.Z.A. Faculdade de Ciências Universidade de Lisboa C2, 1749-016 Lisboa, Portugal pmarques@fc.ul.pt

ABSTRACT This is the first study of the breeding biology of Spanish sparrow Passer hispaniolensis in Portugal, and the second in Western Europe. Our aim in this study is to determine the breeding parameters for the western population and to study the variation within and between years. Seven colonies and 339 nests were studied during three years (1999-2001) in southern Portugal. Breeding occurred from late March or early April until early July or mid July, with time for individuals to have two breeding attempts per year.

Clutch size, 4.90±0.04, was similar to reports by other authors. Hatching success 67.14%, fledgling success 47.39%, number of fledgling per nest 2.77±0.07, and breeding success 31.98% were lower than the reported for North Africa and Eastern populations. c. 55% of the nests produced at least one young.

Variation in productivity between colonies and between years, suggests that local and temporal environmental conditions restrain the sparrows breeding performance. The high degree of breeding synchronisation and short breeding cycle duration combined with strong sociability and nomadic behaviour enhances the species ability to take advantage of short-term highly favourable breeding conditions, characteristic of some breeding habitats of Spanish sparrow.

INTRODUCTION Knowledge of breeding parameters is particularly important in species with conservation problems, or with impact in human activities (Feare 1991, Green & Hirons 1991), like Spanish sparrow Passer hispaniolensis. This species is mainly a seedeater (Alonso 1985) that can become a serious problem in cereal cultivation in marginal semi-arid areas (Summers-Smith 1988, Gavrilov et al. 1995). Spanish sparrow is the most gregarious sparrow in the Palearctic. It breeds in dense colonies of several tree species (e. g. olive groves Olea europea; Eucalyptus or Populus plantations), other bird nests (e. g. storks), and in man-made structures (Sacarrão & Soares 1975, Alonso 1982, Rodriguez-Teijeiro & 2

2. Some ecological considerations

Cordero 1983, Summers-Smith 1988, Metzmacher 1990, Cramp & Perrins 1994). It has a typical Mediterranean distribution extending east into West Central Asia in steppe and semi-desert valleys (Cramp and Perrins 1994). Over this area the species has two subspecies, the western P. h. hispaniolensis and the eastern P. h. transcaspicus with a boundary not clearly marked near Turkey (Summers-Smith 1988).

In Iberia, P. h. hispaniolensis is associated with cereal crops that alternate with fallow and grazing grounds that may or may not include trees (Sacarrão & Soares 1975, Alonso 1982). This is the first study of breeding biology of Spanish sparrow in Portugal, and the second in Western Europe. Our aim in this study is to determine breeding parameters for the species western population, and to analyse their variation within and between years.

MATERIAL AND METHODS During the breeding seasons of 1999, 2000 and 2001 breeding biology of Spanish sparrow was studied in Castro Verde region (37° 41'N, 08° 03'W, Alentejo – southern Portugal). This is a cereal steppe with cereal crops alternating with fallow. Small Eucalyptus plantations and olive groves that abound in the area are used as breeding sites. Fallow is usually land for grazing sheep and cow. The study area was weekly visited from the beginning of March to mid July to find colonies. Seven colonies were studied in order to determine breeding parameters of the species, (one in 1999, three in 2000 and three in 2001), three in olive grove and four in Eucalyptus plantations. The study reports to 1st clutches, with exception of the 2000 end of season colony which include some 2nd clutches. A total of 339 nests were studied, 58 in 1999, 105 in 2000 and 176 in 2001. Nests were checked every 2-4 days.

Clutch size, viability rate (percentage of eggs that hatched considering the laid eggs that were not predated, abandoned or broken), hatching success (percentage of eggs that hatched successfully from all the laid eggs, considering all clutches), brood size, number of fledgling per nest, fledgling success (percentage young fledged from all hatched eggs) and breeding success (percentage of young fledged from all the laid eggs, considering all clutches), were determined for each colony and for each year in order to compare the breeding performance within and between breeding seasons. The visits to colonies and nests permitted observation of the beginning, and duration of the breeding cycle, and the duration of the nesting stages (nest construction, laying, incubation and feeding nestling). Nests were considered successful if they survived until at least the 10th day after hatching.

The mean egg hatching and young fledgling in successful incubated clutches was determined for each clutch size. Pearson’s product-moment correlation between clutch size and mean number of hatching and fledgling per clutch was calculated.

Statistical analysis was performed using the Statistica (StatSoft 1996). Results are presented as mean ± SE (standard error of mean).

RESULTS Phenology The breeding season lasted between 84 days in 1999 and 98 in 2001 and the sparrows started building the nests between late March and early April. At this stage, colonies are unstable and are easily

abandoned: five out of seven colonies abandoned in the beginning of 2001 breeding season. Nest building ranged between five and ten days. In one colony construction was extended 21 days, probably due to adverse weather conditions. Nest building continued during laying phase, namely completing the lining.

In all colonies (n=5) laying was closely synchronised, with 76-91% of first eggs being laid within five days. In most nests, incubation started during the egg-laying period in the 3rd or 4th day. Hatching occurred 9.03±0.06 days (n=185) after the end of the laying period. The mean nestling period was 11.58±0.16 days (n=48) ranging between 10 and 14 days. The duration of breeding cycle (days between laying and fledgling) was 26.36±0.34 days (n=14).

Egg laying and hatching Mean clutch size was 4.90±0.04 (n=333) ranging from 3 to 6 eggs (mode 5). Median clutch size changed significantly during season (Kruskal-Wallis test: H (2, n=103) = 16.15, P<0.01 in 2000 and Kruskal-Wallis test: H (2, n=173) = 21.32, P<0.01 in 2001), early colonies had smaller clutches than later ones (Table 1). No differences were found between years in clutch size (Kruskal-Wallis test: H (2, n=333) = 3.06, ns).

The viability rate in the colonies ranged between 84.52% (n=34) and 71.13% (n=51). Excluding the 2000 end of season colony, results suggest the existence of a trend to the decrease of viability rate over the breeding season (Table 1).

Hatching success was 67.14% (1093 eggs hatched), ranging from 63.32% in 1999 to 69.23% in 2001 (Table 1).

Mean brood size for the three years was 3.78±0.06 (n=289, range 1 to 6). Brood size did not differ significantly between years (Kruskal-Wallis test: H (2, n=289) = 1.85, ns). Brood size changed significantly along the breeding season in both 2000 and 2001 (Kruskal-Wallis test: H (2. n=86)=21.15, P<0.00 and H (2, n=157)=11.71, P=0.003), but with no clear trend (Table 1).

Nestling survival and fledgling Nestling mortality was higher in their first days of life: 30.08% of the nestlings died with 3 or fewer days and 64.69% with less than 5 days. Although an exact assessment of the causes of nestling mortality and nest failure was not possible, predation can be suggested as a major factor. Brood reduction occurred in 71.9% of the successful nests (n=185).

The total fledgling success (from hatching to fledgling, n=289) was 47.39%, varying from 14.46% to 68.57%. Each successful nest produced 2.77±0.07 fledgling (n=187), ranging between one and five. As expected, the number of fledglings per clutch was positively and significantly correlated with clutch size (Pearson r= 0.984; P=0.002) (Table 2). The number of young fledged differs significantly between years (Kruskal-Wallis test: H (2, n=187)=15.07, P<0.00). In 2001 the number of young fledged changed significantly during the breeding season (Kruskal-Wallis test: H (2, n=92)=12.75, P=0.002) but not in 2000 (Kruskal-Wallis test: H (2, n=58)=0.31, ns). Results obtained for 2001 colonies indicate that the number of nestlings fledged increased during the breeding season (Table 1).

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Table 1 Year and seasonal variation of Spanish sparrow clutch size, brood size, number of fledglings, viability rate, hatching success, fledgling success and breeding success in southern Portugal Clutch size

Number of

Viability rate Hatching

Fledgling

Breeding

fledglings (n)

% (n)

success

success

success

3.97±0.11 (46)

3.32±0.16 (37)

79.22 (46)

63.32

67.21

42.56

4.50±0.13 (22)

3.56±0.26 (18)

2.56±0.29 (9)

77.1 (18)

64.00

35.94

23.00

Mid

4.87±0.09 (45)

3.32±0.14 (37)

2.39±2.22 (28)

67.21 (37)

54.91

56.30

30.59

End

5.17±0.11 (35)

4.43±0.17 (32)

2.52±0.21(21)

84.52 (32)

78.45

37.32

29.28

Total

4.89±0.07 (102)

3.78±0.11 (87)

2.47±0.14 (58)

75.8 (87)

65.15

44.00

28.60

Beginning

4.61±0.17 (49)

3.79±0.15 (42)

2.09±0.21 (11)

83.24 (42)

70.04

14.46

10.13

Mid

5.15±0.07 (67)

3.92±0.12 (64)

2.60±0.14 (42)

75.83 (64)

72.75

43.42

31.59

End

4.71±0.10 (58)

3.43±0.11 (51)

3.03±0.13 (39)

71.13 (51)

64.10

68.57

43.96

Total

4.85±0.05 (174)

3.72±0.8 (157)

2.74±0.10 (92)

76.17 (157)

69.23

43.08

29.82

Year

Season

1999

Total

4.98±0.11 (58)

2000

Beginning

2001

eggs (n)

Brood size (n)

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Table 2 Variation of Spanish sparrow hatching success and breeding success with clutch size in southern Portugal Clutch

nº clutches (%)

size

nº of hatched eggs

Hatching

nº fledglings

Breeding

per clutch

success

per clutch

success

3

11 (3.3)

1.63

54.55

0.55

18.00

4

61 (18.4)

2.66

66.39

1.30

32.38

5

209 (63.0)

3.37

67.46

1.55

30.91

6

51 (15.4)

4.08

68.00

2.16

35.95

Total

332

3.29

67.13

1.57

32.01

Total breeding success of the studied population was 31.82% (n=334), this parameter varied greatly ranging from 10.13% to 43.96%. The proportion of eggs that produced fledglings vary significantly between years (χ2=12.78, df=2, P<0.002) and within the 2001 season (χ2=48.415, df=2, P<0.001) but not in 2000 (χ2=1.43, df=2, ns). Breeding success was highest, in the year 2001 (Table 1).

About 55 % of the 336 nests produced at least one fledgling, ranging between 52.57% (in 2001) and 63.70% (in 1999). The variation within season was even more accentuated, ranging from 39.13% to 62.22% in 2000 and from 22.0% raising to 67.24% in 2001.

On several occasions, predator taking a single nestling was observed. The recording of this behaviour excludes the common assumption that predators only causes total nest failure (Murphy & Haukioja 1986, Montgomerie & Weatherhead 1988, Muñoz-Pulido et al. 1990, Martin 1995), making predation difficult to distinguish from other causes of nestling mortality.

DISCUSSION The start of the breeding season is similar to the rest of Europe (Sacarrão & Soares 1975, SummersSmith 1988), but in some years can be earlier than in Spain (Alonso 1982). Duration of the breeding season was shorter than in Spain, 84-98 days against 98-100 days (Alonso 1982). These results combined with the duration of the breeding cycle suggest that if a 3rd clutch occurs, it is only laid in some years; Results from Spain support this (Alonso 1982, 1984). In other regions, the number of breeding attempts was usually two or even one in arid habitats (Cramp & Perrins 1994). These results can be misleading because Spanish sparrow populations are nomadic in most of their range and can breed during one season in more than one location (Baumgart 1980 in Summers-Smith 1988), making the number of breeding attempts difficult to assess. The high degree of breeding synchronisation within colonies obtain in this study was similar to the reported by other authors (Gavrilov 1963, Alonso 1984, Metzmacher 1990).

The overall clutch size (4.90±0.04 eggs/clutch) is similar to the one reported by Alonso in Spain, 5.0±0.03 (Alonso 1982) and to results for other populations compiled by Cramp & Perrins (1994).

Seasonal variation of clutch size could be related to the variation of available food, reflecting the 6

adjustments of clutch size to the predictive environmental conditions during nestling growth (Lack 1954 in Murphy 1978).

Nestling mortality was higher in the early phase of nestling growth. Alonsoâ&#x20AC;&#x2122;s (1982) results agreed with this, but present a stronger effect, 79.08% of nestling mortality occurred between two and six days of age, against 64.69% (one to five days) in this study.

The results concerning hatching success, fledgling success, number of fledglings per nest and breeding success were lower than those reported by other authors for North Africa (e.g breeding success Algeria 50% - 53.4%: Metzmacher 1990) and Eastern populations (e.g breeding success Kazakhstan 57%: Gavrilov 1963; from Cramp and Perrins 1994), but similar to results from Spain (e. g breeding success 35.5%: Alonso 1982, 1984).

The reported variability in this study, namely in productivity, between years, suggests that temporal environmental conditions (such as food availability and predation) can restrain breeding performance.

The variation within colonies suggests that there are important differences in individual quality, or in the effect of breeding success constraining factors within the breeding population, with only a part of the population producing offspring (55.56% of the nests).

The timing of reproduction and nest site selection should be under a strong selective pressure in a species building conspicuous straw nests in the branches of the trees. The high degree of breeding synchronisation and short breeding cycle duration, combined with strong coloniality and nomadic behaviour to enhance its ability to exploit favourable conditions for breeding, characteristic of some breeding habitats of Spanish sparrow (Baumgart 1980 in Summers-Smith 1988, Alonso 1984). This could be one of the adaptive advantages of living in colonies in this species, with old and experienced birds, more able to assess patch quality, choosing the breeding site (Danchin et al. 1998, Brown & Brown 2000). Synchronised breeding in dense colonies also plays an important role in predator avoidance (Alonso 1984). These characteristics enhance its ability to take advantage of short-term favourable breeding conditions (Alonso 1984, Summers-Smith 1988) and exploit resources that are inaccessible to other species.

SUMMARY 1.

This is the first study of the breeding biology of Spanish sparrow in Portugal. Seven colonies and 339 nests were studied during three years 1999-2001.

2.

Egg laying occurred from late March or early April until early July or mid July, with time for individuals to have two breeding attempts per year. The breeding season lasted between 84 days in 1999 and 98 in 2001.

3.

The determined breeding parameters for the population were: clutch size 4.90Âą0.04, hatching success 67.14%, fledgling success 47.39%, number of fledgling per nest 2.77Âą0.07, breeding success 31.70%, and 55%-56% of the nests produced at least one young.

4.

These breeding parameters were lower than the reported for North Africa and Eastern populations.

5.

Reported variability in this study between years suggests that temporal environmental conditions

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restrain the sparrows breeding performance.

6.

The high degree of breeding synchronisation and short breeding cycle duration combined with strong sociability and nomadic behaviour enhance the species ability to exploit periods of highly favourable conditions for breeding, characteristic of some breeding habitats of Spanish sparrow.

ACKNOWLEDGEMENTS A. M. Costa, I. Moreira, A. João, A. Marques and C. Moura helped during field work. L. Vicente, M.

O. Jorge made helpful comments on earlier drafts of this manuscript. I appreciate the improvements in English usage made by R. Braucht through the Association of Field Ornithologists' program of editorial assistance. PMM was supported by funds from Fundação da Ciência e Tecnologia (grant PRAXISXXI/BD/16002/98).

REFERENCES Alonso, J. C. 1982. Contribución a la biología del Gorrión moruno, Passer hispaniolensis (Temm.) en la Peninsula Ibérica y sus relaciones ecológicas con el Gorrión común, Passer domesticus (L.). Ph. D. thesis, Universidad Complutense.

Alonso, J. C. 1984. Estudio comparado de los principales parámetros reprodutivos de Passer hispaniolensis y Passer domesticus en España centro-occidental. - Ardeola 30: 3-21.

Alonso, J. C. 1985. La alimentacíon del Gorrión moruno (Passer hispaniolensis) en áreas de cultivo de regadio extremañas. - Donaña, Acta Vertebrata 12: 251-263.

Brown, C. R. & Brown, M. B. 2000. Nest spacing in relation to settlement time in colonial Cliff swallows. - Animal Behaviour 59: 47-55.

Cramp, S. & Perrins, C. M. 1994. The birds of the Western Palearctic. - Oxford University Press, Oxford.

Danchin, E., Boulinier, T. & Massot, M. 1998. Conspecific reproductive success and breeding habitat selection: implication for the study of coloniality. - Ecology 79: 2415-2428.

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Gavrilov, E. 1963. The biology of the Eastern Spanish sparrow, Passer hispaniolensis transcaspicus Tschusi, in Kazakhstan. - Journal of the Bombay Natural History Society 60: 301-317.

Gavrilov, E., Erokhov, S., Grjaznov, A., Brokhovich, S. & Goloshchapov, A. 1995. Number evaluation of migratory sparrows inhabiting south-eastern Kazakhstan and northern Kirgizstan. - In: Pinowski, J., Kavanagh, B. P. & Pinowska, B. (eds). Nestling mortality of granivorous birds due to microorganisms and toxic substances: synthesis. Polish Scientific Publishers, Warszawa, pp.

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Green, R. E. & Hirons, G. J. M. 1991. The relevance of population studies to the conservation of threatened birds. - In: Perrins, C. M. & Lebreton, J.-D. (eds). Bird population studies relevance to conservation and management. Oxford University Press, Oxford, pp. 594-633.

Martin, T. E. 1995. Avian life history evolution in relation to nest sites, nest predation, and food. Ecological Monographs 65: 101-127.

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Metzmacher, M. 1990. Climatic factors, activity budgets and breeding success of the Spanish sparrow [Passer hispaniolensis (Temm.)]. - In: Pinowski, J. & Summers-Smith, J. D. (eds). Granivorous birds in the agricultural landscape. Polish Scientific Publishers, Warszawa, pp. 151-168.

Montgomerie, R. & Weatherhead, P. J. 1988. Risks and rewards of nest defence by parent birds. Quarterly Review of Biology 2: 167-187.

Muñoz-Pulido, R., Bautista, L. M., Alonso, J. C. & Alonso, J. A. 1990. Breeding success of Azurewinged magpies Cyanopica cyana in Central Spain. - Bird Study 37: 111-114.

Murphy, E. C. 1978. Seasonal variation in the reproductive output of House sparrows: the determination of clutch size. - Ecology 59: 1189-1199.

Murphy, E. C. & Haukioja, E. 1986. Clutch size in nidicolous birds. - Current Ornithology 4: 141-180.

Rodriguez-Teijeiro, J. D. & Cordero, P. J. 1983. Orientación y selección del lugar del nido en el Gorrión moruno (Passer hispaniolensis). - Donaña, Acta Vertebrata 10: 77-90.

Sacarrão, G. F. & Soares, A. A. 1975. Algumas observações sobre a biologia de Passer hispaniolensis (Temm.) em Portugal. - Estudos sobre a Fauna Portuguesa 8: 1-14.

StatSoft, I. 1996. STATISTICA for Windows [Computer program manual]. Tulsa, OK. Summers-Smith, J. D. 1988. The Sparrows - A study of the genus Passer. - Poyser, London.

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