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Buffering against food availability? The physical environment has little influence on breeding performance of fairy prions ( P achyptila turtur )
Author(s) -
Manno Katharina,
Loh Graeme,
Van Heezik Yolanda
Publication year - 2014
Publication title -
austral ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.688
H-Index - 87
eISSN - 1442-9993
pISSN - 1442-9985
DOI - 10.1111/aec.12115
Subject(s) - fledge , predation , competition (biology) , biology , ecology , reproductive success , nest (protein structural motif) , seabird , apex predator , zoology , demography , population , biochemistry , sociology
The breeding performance of seabirds is constrained by the availability of marine‐based prey, which may be influenced by competition with other seabirds, and environmental conditions. Fairy prion ( P achyptila turtur ) populations have declined substantially in N ew Z ealand since the introduction of mammalian predators; remaining small populations provide an opportunity to examine the effect of environmental factors on reproductive success in the absence of competition. Using 11 years of nest monitoring data and eight years of chick measurements we investigated (i) the link between physical environmental factors, breeding success rates and chick fledging size, and (ii) the relationship between chick fledging size and likelihood of natal‐colony recapture. Despite annual variations in the S outhern O scillation I ndex ( SOI ) and sea surface temperatures ( SST ), breeding success and chick fledging weights remained similar throughout the entire period, possibly due to the use of behavioural buffering mechanisms by parents. Fledgling wing lengths differed among years, and were predicted by early winter and early spring values of the SOI and late spring and summer SSTs . In years of high SOI and high SST , fairy prions fledged with longer wings, possibly due to increased availability of the euphausiid N yctiphanes australis , their main prey. River flows and rainfall were unrelated to breeding success or chick measurements: the influence of freshwater on the marine system at this locality acts at smaller timescales than those studied here. Using the 2004 and 2005 cohorts, there was no link between fledging size and likelihood of recapture, except for the 2005 cohort which had unusually low 6‐year recapture rates, and shorter‐than‐average wing lengths. A combination of low sea temperatures and an E l N iño event in 2005 may have led to a reduction in euphausiid availability, ultimately affecting post‐fledging survival.