Foraging decisions of Sandwich Terns in the presence of kleptoparasitising gulls
Stienen, E.W.M.; Brenninkmeijer, A. (2005). Foraging decisions of Sandwich Terns in the presence of kleptoparasitising gulls, in: Stienen, E.W.M. Living with gulls: trading off food and predation in the Sandwich Tern Sterna sandvicensis. Alterra Scientific Contributions, 15: pp. 61-79
In: Stienen, E.W.M. (2005). Living with gulls: trading off food and predation in the Sandwich Tern Sterna sandvicensis. Alterra Scientific Contributions, 15. PhD Thesis. Rijksuniversiteit Groningen: Groningen. ISBN 90-367-2480-5. 192 pp., more
In: Alterra Scientific Contributions. Alterra: Wageningen, more
|
| Keywords |
Aquatic organisms > Marine organisms > Aquatic birds > Marine birds
Behaviour > Feeding behaviour > Foraging behaviour
Gulls
Interspecific relationships > Competition
Interspecific relationships > Predation > Prey selection
Larus ridibundus Linnaeus, 1766 [WoRMS]; Sterna sandvicensis Latham, 1787 [WoRMS]
Marine/Coastal; Brackish water |
| Abstract |
We studied prey selection of Sandwich Terns (Sterna sandvicensis) in the presence of kleptoparasitising Black-headed Gulls (Larus ridibundus) on Griend, Dutch Wadden Sea, from 1992 to 1998. Most often, gulls robbed larger sandeels rather than herring from terns. Provided that one parent attends the chick, energy intake would be too low for the chicks' survival if exclusively fed on sandeel. By provisioning an increasing proportion of herring, parent terns could theoretically overcome a potential food shortage when the chicks grow older. However, the proportion of herring did not increase with age of chicks in most years. Instead, parents increased their foraging effort with the growth of their offspring. In years with high proportions of food loss, parents left their chicks unattended at the nest more often. In that way, parents were largely able to counterbalance food shortage of offspring. In 1992 and 1996, when diet composition was unfavorable and food losses to gulls were high, parents left their chicks unattended at the nest for 680% of the daylight period. It is argued that the present working level of parents might be higher than in the 1960s. |
| Datasets (2) |
- Data Institute for Nature Conservation, more
- Data Institute for Nature Conservation, more
|
|
