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Garcia G.O.,CONICET | Garcia G.O.,University of the Sea | Becker P.H.,Institute For Vogelforschung | Favero M.,CONICET | Favero M.,University of the Sea
Journal of Ornithology | Year: 2011

Kleptoparasitism is a well-known foraging tactic used opportunistically by many seabird species. However, little is known about this behaviour during the early stages of the breeding cycle and its effects on breeding performance. Here, we investigated the relationship between kleptoparasitism during the courtship period and female reproductive performance in Common Terns (Sterna hirundo). All identified kleptoparasites were males, and none of their mates performed such behaviour. We compared two groups of tern pairs, one where the males performed kleptoparasitism (kleptoparasitic group, n = 10), the other one where both mates were non-kleptoparasitic (honest group, n = 22). The body mass of kleptoparasitic females was between 8 and 15% higher than that of honest females. In kleptoparasitic females, the third egg was significantly bigger than in honest birds, and the egg-volume was not significantly different between the three eggs of the clutch in contrast to honest birds. We found no differences in the comparison among hatching success between both groups. The reproductive output, however, was significantly higher in the kleptoparasitic than in the honest group. Hence, we are providing the first evidence that kleptoparasitism during early stages of the breeding cycle has a strong link with egg size and reproductive output in Common Terns. © 2010 Dt. Ornithologen-Gesellschaft e.V. Source


De Boer R.,Netherlands Institute of Ecology | Bauer S.,Netherlands Institute of Ecology | Van Der Jeugd H.P.,Sovon Vogelonderzoek Nederland | Van Der Jeugd H.P.,Netherlands Institute of Ecology | And 6 more authors.
Limosa | Year: 2014

With the help of GPS technology it has recently become possible to track individual birds on migration in great detail. In this study we use GPS satellite transmitters to compare spring migration of three populations of Barnacle Goose in space and time: the Russian, Svalbard and Greenland populations. Populations differed in their migration patterns and stopover use, which can be related to differences in routes, in particular whether they had to cross any large-scale barriers during migration (Tab. 1, Fig. 1). Within populations, however, migration patterns also differed remarkably between individuals, especially in the Svalbard and Russian populations, with some individuals even'skipping'stopovers altogether and flying 'directly' to the breeding grounds (Fig. 2). Within the Greenland population less variability was observed, possibly because these birds need to cross two stretches of ocean during spring migration, which might not allow for variation in migration patterns. Overall, Barnacle geese show a remarkable variability in individual migration patterns. Source


Randler C.,University of Education, Heidelberg | Forschler M.I.,Institute For Vogelforschung | Gonzalez J.,University of Heidelberg | Aliabadian M.,Ferdowsi University of Mashhad | And 2 more authors.
Journal of Ornithology | Year: 2012

The insular endemic Cyprus Wheatear Oenanthe cypriaca has been considered as a subspecies of Pied Wheatear O. pleschanka. However, due to several differences in behaviour, habitat selection and morphology, it is currently treated by most authors as an independent species. Here, we used mitochondrial nucleotide sequences of the cytochrome oxidase subunit 1 gene (679 base pairs), playback experiments and dummy presentations to assess the status of O. cypriaca. For the playback experiments we used the conspecific song, and heterospecific songs of the two subspecies of Black-eared Wheatear O. hispanica hispanica and O. hispanicamelanoleuca, O. pleschanka, and Finsch's Wheatear O. finschii. Experimental dummy presentations included O. cypriaca, O. pleschanka and a dark and light morph of O. h. melanoleuca. O. cypriaca responded significantly stronger towards the conspecific model and towards conspecific playbacks than towards heterospecific stimuli. ML and BI analyses support the close relationship between O. cypriaca, O. pleschanka and O. h. melanoleuca. With a relative high posterior probability value (0.98), O. cypriaca clusters closer to O.h. melanoleuca from Iran and Israel (on migration) and O. pleschanka from Iran than to O. pleschanka obtained from Kazakhstan, Russia, Mongolia and wintering areas in East Africa (Kenya). The scenario suggests that O. cypriaca might be either a relatively young taxon, which is yet behavioural distinct, but genetically still similar to its sister populations on the mainland. Alternatively, we may assume a close relationship as an indication for potential ongoing hybridisation processes involving all three forms. © 2011 Dt. Ornithologen-Gesellschaft e.V. Source


Limmer B.,Institute For Vogelforschung | Becker P.H.,Institute For Vogelforschung
Oikos | Year: 2010

Reproductive success increases with age in many species, however, the underlying mechanisms remain unclear and several hypotheses have been proposed to explain age-related improvements in reproductive output. In this contribution we investigated the effects of age, recruitment age, breeding experience and sex on reproductive performance during the early breeding career in the common tern Sterna hirundo using long-term individual-based data. We used measurements of performance, which spanned the entire breeding process: clutch size, hatching success, fledging success and fledglings per pair. Longitudinal analyses within individuals showed a clear increase with age in all performance measures. Furthermore, a significant change in reproductive performance was found between first time- and experienced breeders. Recruitment age had a strong influence on hatching and fledging success: two-year-old recruits had significantly lower reproductive success than birds which recruited at older ages, but the increase in breeding performance with experience was stronger in young recruits. Comparing age and experience effects, age effects were more pronounced during the first breeding attempts, whereas experience effects were also visible in subsequent breeding attempts. The degree of intra-individual improvements in reproductive performance is due to a complex interplay of age at first breeding and experience. The results strongly support the constraint hypothesis. © 2009 The Authors. Journal compilation © 2010 Oikos. Source

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