Barrow's Goldeneye

One thing which happens frequently is that all the arriving young join the resident
ones and the arriving female leaves the area alone and does not take up a territory.


All the resident young join the arriving female and leave their territory with her.
She moves downstream and takes up a territory there.
The territorial female, which now has lost all her young, stays on the territory
for a day or two and then abandons it.

What is the advantage of all this?
Are the arriving females trying to smuggle their young into the good territories?
Are  the territorial females attracting young in order to make their own young
less vulnerable to predation?
Or is this just a result of the crowded conditions prevailing
in the outlet area where food is very abundant?
What do YOU think?

Keeping a territory in the best feeding area has its COSTS!


Árni Einarsson 1985. Use of space in relation to food in Icelandic Barrow's goldeneye (Bucephala islandica).  Ph.D. thesis, University of Aberdeen, Scotland.

Árni Einarsson 1985. Dreifing húsanda með tilliti til fæðu. Bliki 4: 67-69.

Árni Einarsson 1988. Distribution and movements of Barrow's goldeneye Bucephala islandica young in relation to food. Ibis 130: 153-163.