2010/02/24 by Julia Sommerfeld, Janos C. Hennicke · 35 citations
Environmental Science · Earth and Planetary Sciences · Engineering · #Avian ecology and behavior #Marine and fisheries research #Tropical and Extratropical Cyclones Research #Foraging #Incubation #Food delivery #TRIPS architecture #Biology #Ecology #Animal science #Duration (music) #Zoology #Fishery #Advertising #Engineering
paper · doi:10.1071/mu09053
published in Emu - Austral Ornithology 110(1), 78-86 (Taylor & Francis)
openalex publication_date 2010/02/24 · openalex created_date 2025/10/10 · openalex updated_date 2026/05/09
In the tropical marine environment food resources are scarce and often patchily distributed. Consequently, nesting tropical seabirds must balance travelling to productive areas and sharing incubation or providing food to the chick. Changes in foraging behaviour occur when adults switch from feeding only for themselves during incubation to feeding a chick and fulfilling their own energy requirements. Externally attached data-devices were used to compare the duration of foraging trips, flight activity and depth of dives of incubating and chick-rearing Red-tailed Tropicbirds (Phaethon rubricauda) on Christmas Island, Indian Ocean. Adults with chicks had a bimodal pattern of foraging, with alternating short and long foraging trips (mean duration±s.d. of short trips = 3.0 ± 4.1 h, of long trips = 57.4 ± 41.1 h), whereas incubating adults undertook only longer trips (mean duration ± s.d. = 152.9 ± 47.2 h). This strategy is stimulated by partner behaviour, rather than body mass as reported for many other seabirds, and may enable the optimisation of simultaneous food delivery to chicks and self-feeding when local resources are poor. The proportion of time spent in flight (flight activity) by adults with chicks averaged 90.1% during short trips whereas incubating birds spent only 62.4% of their trips flying. Overall mean depth of foraging dives by adults with chicks averaged 0.6 ± 0.3 m during short trips; mean maximum depth of dives by incubating adults were recorded using maximum-depth recorders and were significantly deeper at 10.7 ± 8.7 m, reaching a maximum depth of 25.6 m.