Isotopic niche segregation during the non-breeding period in Black-faced Cormorants (Phalacrocorax fuscescens)
Cansse, T.; Lens, L.; Lepoint, G.; Arnould, J.P.Y. (2025). Isotopic niche segregation during the non-breeding period in Black-faced Cormorants (Phalacrocorax fuscescens). Emu 125(3): 214-225. https://dx.doi.org/10.1080/01584197.2025.2528606
In: Emu: journal of the Royal Australasian Ornithologists Union. CSIRO Publishing (Commonwealth Scientific and Industrial Research Organization): Melbourne. ISSN 0158-4197; e-ISSN 1448-5540, more
|  |
| Author keywords |
Seabird;cormorant;Bass Strait;non-breeding period;stable isotopes;stable-isotopes;foraging behavior;climate-change;feathers;carbon;blood;ecology;diet |
| Authors | | Top |
- Cansse, T., more
- Lens, L., more
- Lepoint, G., more
- Arnould, J.P.Y.
|
|
|
| Abstract |
Due to environmental changes, prey distribution and availability are predicted to change. This is expected to impact their predators, especially in the highly dynamic and fast-changing marine environment. To predict these impacts, knowledge of predator diets throughout the annual cycle is needed. During the breeding season, collecting diet samples from seabirds is relatively simple, but data on other periods are harder to obtain. To study trophic niche during the non-breeding period, stable isotopes extracted from feathers can be used as a proxy. Bulk stable isotope ratios of carbon (13C/12C), nitrogen (15N/14N) and sulphur (34S/32S) of feathers (n = 96), blood (n = 10) and gut content (n = 56) were combined with GPS tracking data (n = 30) to study the trophic niche, individual niche consistency and the link between non-breeding trophic niche and habitat use in Black-faced Cormorants (Phalacrocorax fuscescens). On the population level, a large range in isotope compositions (combination of C, N and S isotope ratios) was observed, indicating that individuals exploit diverse prey and habitats. However, comparing blood (breeding) and feather (non-breeding) stable isotope data from the same individuals revealed little within-individual variation in isotope compositions, indicating individual consistency in exploited prey or habitats. Tracking data revealed that delta 13C, delta 15N and delta 34S values in feathers reflected whether an individual foraged in shallow or deeper habitats during the non-breeding period and may be used to monitor habitat use. This study provides further insights into the year-round diet and foraging of the poorly studied Black-faced Cormorant. |
|
