Distribution of pair quality in a tree-nesting waterbird colony: central-periphery model vs. satellite model

2012 ◽  
Vol 90 (7) ◽  
pp. 861-867 ◽  
Author(s):  
Piotr Minias ◽  
Krzysztof Kaczmarek ◽  
Tomasz Janiszewski
Keyword(s):  
Clutch Size ◽  
Theoretical Models ◽  
Predation Rate ◽  
Site Quality ◽  
Laying Date ◽  
Great Cormorant ◽  
Phalacrocorax Carbo ◽  
Fledging Success ◽  
Heterogeneous Habitats ◽  
Nesting Sites

The spatial distribution of pair quality within waterbird colonies has been suggested to follow one of three theoretical models: central-periphery, satellite, or random. The central-periphery pattern occurs in homogeneous habitats, where good-quality pairs occupy better protected, central nesting sites. In contrast, the satellite and random patterns are associated with heterogeneous habitats and they assume that good-quality pairs occupy the most attractive nesting sites irrespectively of their location within the colony. Spatial patterns of laying date, clutch size, and fledging success were analysed with geostatistical tools in the colony of tree-nesting subspecies of Great Cormorant ( Phalacrocorax carbo sinensis (Blumenbach, 1798)) in central Poland. There was support for the random or satellite model in the distribution of clutch size, which was considered a reliable proxy of pair quality. We also found a positive correlation of clutch size with nest height. These results implicate that the habitat of tree-nesting colonial waterbirds may produce sufficient variation in the nesting-site quality to disrupt the central-periphery gradients of pair-quality distribution. In contrast, distribution of fledging success within the colony followed a clear central-periphery pattern, which was suggested to reflect an increased predation rate at the edges of the colony, rather than the intrinsic quality of breeding birds.

Reproduction du Grand Cormoran (Phalacrocorax carbo) et du Cormoran à aigrettes (P. auritus) aux îles de la Madeleine, Québec

1983 ◽  
Vol 61 (3) ◽  
pp. 524-530 ◽  
Author(s):  
Christian Pilon ◽  
Jean Burton ◽  
Raymond McNeil
Keyword(s):  
Mortality Rate ◽  
Clutch Size ◽  
Hatching Success ◽  
Great Cormorant ◽  
Phalacrocorax Carbo ◽  
Different Types ◽  
Nesting Sites ◽  
The Mean ◽  
Great Cormorants ◽  
La Madeleine

The Great Cormorant (Phalacrocorax carbo) and the Double-crested Cormorant (P. auritus) on the Magdalen Islands (Québec) nest in different types of habitat; all Great Cormorants nest on the ground either on cliff ledges or on the flat tops of rocky islands, while all Double-crested Cormorants nest in coniferous trees. No mixed colonies were seen in 1977 and 1978. Most Great Cormorants laid their eggs some 10 days before the Double-crested Cormorants. The mean clutch size was 4.4 for the Great Cormorant in 1978 and 3.2 and 3.6 for the Double-crested Cormorant in 1977 and 1978. The hatching success was similar for both species, 69.2% for the Great Cormorant in 1978 and 74.5 and 71.8% for the Double-crested Cormorant in 1977 and 1978. Great Cormorant chicks had a higher mortality rate mainly during their first 2 weeks of like. This resulted in a similar ratio of young fledged for both species of cormorant, about 2.0 fledglings per clutch for the Great Cormorant and 2.1 and 2.4 fledglings per clutch for the Double-crested Cormorant in 1977 and 1978. The greater mortality rate of young Great Cormorants reflects differences in nesting sites' conditions.

scholarly journals Breeding biology of a relictual Maghreb Magpie (Pica mauritanica) population in Tunisia

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Aymen Nefla ◽  
Ridha Ouni ◽  
Slaheddine Selmi ◽  
Saïd Nouira
Keyword(s):  
Clutch Size ◽  
Rattus Rattus ◽  
Egg Laying ◽  
Breeding Biology ◽  
Laying Date ◽  
Rank Test ◽  
Detailed Data ◽  
Egg Volume ◽  
Fledging Success ◽  
Relic Population

Abstract Background The Maghreb Magpie (Pica mauritanica) is an endemic North African species. Available knowledge on this species is limited to historic descriptive data with no ecological information provided. Populations continue to dramatically decline in Tunisia, where only one relic population survives. Investigating the breeding biology of this species is essential for conservation purposes. The purpose of this study was to increase our understanding of the Tunisian relic population and provide detailed data on breeding biology over two breeding seasons (2017 and 2018). Methods This study occurred on a private farm of 650 ha, located 10 km from Dhorbania village at Kairouan Governorate, in central Tunisia. Active nests were monitored weekly during egg laying period and twice a week during hatching period. The Ivlev’s electivity index was used to assess whether the frequency of use of nesting trees and bushes matched their availability in the study area. We recorded nest measurements and positions, and compared them using Wilcoxon signed-rank test. Variations of breeding parameters as number of eggs laid, hatchlings, and fledglings over years were performed using Mann–Whitney U-test and χ2 tests. We used a Generalized Linear Mixed Model (GLMM) to investigate how egg volume varied with clutch size and laying date. Results We investigated clutch size, egg size, hatching and fledging success, and evaluated how these parameters varied according to laying date and nest characteristics. Clutch size averaged 5.00 ± 0.19 but was significantly greater in 2017. Hatching success was 2.78 ± 0.34 eggs hatched per nest and fledging success reached 1.69 ± 0.30 young/nest. Causes of nest failure included the depredation of nestlings by shrikes, cobras and rats (e.g. Lanius meridionalis, Naja haje and Rattus rattus), death of parents by the Black-shouldered Kite (Elanus caeruleus) and nest parasitism by the Great Spotted Cuckoo (Clamator glandarius). Clutch size, brood size and fledgling success were unaffected by laying date, nest volume and nest elevation. Egg volume decreased with laying date but was unaffected by clutch. Conclusion Our study provides the first and only detailed data on reproductive parameters of the Maghreb Magpie in its entire geographic range (North Africa). Information gleaned from this study provides valuable information for monitoring and long-term conservation plans of the endangered Tunisian Magpie population. Additionally, our data provide an avenue of large-scale comparative studies of the reproductive ecology of the magpie complex.

scholarly journals Clutch Enlargement in Lesser Gray Shrikes (Lanius Minor) in Slovakia When Food is Superabundant: A Maladaptive Response?

The Auk ◽  
2004 ◽  
Vol 121 (2) ◽  
pp. 557-564
Author(s):  
Herbert Hoi ◽  
Anton Kristin ◽  
Francisco Valera ◽  
Christine Hoi
Keyword(s):  
Clutch Size ◽  
Egg Laying ◽  
Laying Date ◽  
Breeding Ecology ◽  
Long Distance ◽  
Fledging Success ◽  
Melolontha Melolontha ◽  
Nestling Diet ◽  
Study Population ◽  
Maladaptive Response

Abstract Food abundance influences various aspects of birds' breeding ecology, such as onset of laying, clutch size, and reproductive success. Here, we examine the effects of a natural superabundance of food—cockchafers (Melolontha melolontha, Coleoptera)—on nesting success of a monogamous long-distance migrant, the Lesser Gray Shrike (Lanius minor). In that species, cockchafers make up 88% of adult and 48% of nestling diet in years with cockchafer outbreaks. We compared timing of egg laying, clutch size, and fledging success in three years and chick development in two years with and without cockchafer outbreaks. In cockchafer years, laying date was advanced by about one day, clutch size increased by about one egg, and heavier chicks were produced. Fledging success, however, did not change (fledgling number in non-cockchafer years: 5.3 ± 0.2, 5.0 ± 0.2, and 4.0 ± 0.5; in cockchafer years: 4.1 ± 0.7, 5.4 ± 0.2, and 4.2 ± 0.5), because more eggs failed to hatch during cockchafer years. Thus, increased clutch size in periods of superabundant food do not always result in increased fledgling production. Limited incubation ability or intrinsic physical egg properties, resulting in inefficient incubation, are the most likely explanations for increased hatching failure in years of food superabundance in our study population of Lesser Gray Shrikes.

Summer food of the Great and Double-crested Cormorants on the Magdalen Islands, Quebec

1983 ◽  
Vol 61 (12) ◽  
pp. 2733-2739 ◽  
Author(s):  
Christian Pilon ◽  
Jean Burton ◽  
Raymond McNeil
Keyword(s):  
Clupea Harengus ◽  
Great Cormorant ◽  
Pseudopleuronectes Americanus ◽  
Phalacrocorax Carbo ◽  
Nesting Sites ◽  
Capelin Mallotus Villosus ◽  
Great Cormorants ◽  
Clupea Harengus Harengus ◽  
Associated Species ◽  
Magdalen Islands

This study of the food of the Great Cormorant (Phalacrocorax carbo) and the Double-crested Cormorant (P. auritus) on the Magdalen Islands, Quebec, is based on regurgitations and pellets collected on nesting sites during the summers of 1977 and 1978. Both species generally ate flatfishes (especially the winter flounder, Pseudopleuronectes americanus), American sand lances (Ammodytes americanus) and cunners (Tautogolabrus adspersus). Relatively more Great Cormorants than Double-crested Cormorants ate flatfishes and cunners during both summers, while relatively more Double-crested Cormorants fed on American sand lances during the summer of 1977. These fishes and other prey taken in lesser extent were mostly bottom-associated species; however both cormorants, especially the Double-crested Cormorant, take advantage of Capelin (Mallotus villosus) and Atlantic Herring (Clupea harengus harengus) schools which come spawning close to the seashore. Great and Double-crested cormorants appear to be opportunistic feeders since their diet varies with the availability of prey.

scholarly journals Temporal changes in reproductive success and optimal breeding decisions in a long-distance migratory bird

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Cynthia Reséndiz-Infante ◽  
Gilles Gauthier
Keyword(s):  
Reproductive Success ◽  
Clutch Size ◽  
Environmental Changes ◽  
Migratory Bird ◽  
Laying Date ◽  
Negative Consequences ◽  
Breeding Phenology ◽  
Additional Time ◽  
Long Distance ◽  
Seasonal Decline

AbstractMany avian migrants have not adjusted breeding phenology to climate warming resulting in negative consequences for their offspring. We studied seasonal changes in reproductive success of the greater snow goose (Anser caerulescens atlantica), a long-distance migrant. As the climate warms and plant phenology advances, the mismatch between the timing of gosling hatch and peak nutritive quality of plants will increase. We predicted that optimal laying date yielding highest reproductive success occurred earlier over time and that the seasonal decline in reproductive success increased. Over 25 years, reproductive success of early breeders increased by 42%, producing a steeper seasonal decline in reproductive success. The difference between the laying date producing highest reproductive success and the median laying date of the population increased, which suggests an increase in the selection pressure for that trait. Observed clutch size was lower than clutch size yielding the highest reproductive success for most laying dates. However, at the individual level, clutch size could still be optimal if the additional time required to acquire nutrients to lay extra eggs is compensated by a reduction in reproductive success due to a delayed laying date. Nonetheless, breeding phenology may not respond sufficiently to meet future environmental changes induced by warming temperatures.

Morphological and genetic characterisation of Sarcocystis halieti from the great cormorant (Phalacrocorax carbo)

2018 ◽  
Vol 117 (11) ◽  
pp. 3663-3667 ◽  
Author(s):  
Petras Prakas ◽  
Dalius Butkauskas ◽  
Saulius Švažas ◽  
Vitas Stanevičius
Keyword(s):  
Great Cormorant ◽  
Phalacrocorax Carbo ◽  
Genetic Characterisation

The costs of reproduction in tree swallows (Tachycineta bicolor)

1991 ◽  
Vol 69 (10) ◽  
pp. 2540-2547 ◽  
Author(s):  
Nathaniel T. Wheelwright ◽  
Joanna Leary ◽  
Caragh Fitzgerald
Keyword(s):  
Life History ◽  
Clutch Size ◽  
Brood Size ◽  
Life History Theory ◽  
Tachycineta Bicolor ◽  
Laying Date ◽  
Tree Swallows ◽  
Costs Of Reproduction ◽  
Return Rates ◽  
Trade Offs

We investigated the effect of brood size on nestling growth and survival, parental survival, and future fecundity in tree swallows (Tachycineta bicolor) over a 4-year period (1987–1990) in an effort to understand whether reproductive trade-offs limit clutch size in birds. In addition to examining naturally varying brood sizes in a population on Kent Island, New Brunswick, Canada, we experimentally modified brood sizes, increasing or decreasing the reproductive burdens of females by two offspring. Unlike previous studies, broods of the same females were enlarged or reduced in up to 3 successive years in a search for evidence of cumulative costs of reproduction that might go undetected by a single brood manipulation. Neither observation nor experiment supported the existence of a trade-off between offspring quality and quantity, in contrast with the predictions of life-history theory. Nestling wing length, mass, and tarsus length were unrelated to brood size. Although differences between means were in the direction predicted, few differences were statistically significant, despite large sample sizes. Nestlings from small broods were no more likely to return as breeding adults than nestlings from large broods, but return rates of both groups were very low. Parental return rates were also independent of brood size, and there was no evidence of a negative effect of brood size on future fecundity (laying date, clutch size). Reproductive success, nestling size, and survival did not differ between treatments for females whose broods were manipulated in successive years. Within the range of brood sizes observed in this study, the life-history costs of feeding one or two additional nestlings in tree swallows appear to be slight and cannot explain observed clutch sizes. Costs not measured in this study, such as the production of eggs or postfledging parental care, may be more important in limiting clutch size in birds.

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