This research encompasses both basic (behavioural ecology) and
applied (conservation biology) aspects of the biology of Avocets (Recurvirostra
avosetta L.). My central question is whether adoption of alien young can be
adaptive for adults and the adopted chicks. I evaluate proximate-level hypotheses
by quantifying costs and/or bene�ts of both adopters and adoptees. I observed
adoption of alien chicks in 19% of the families in 1998 and 1999. My �rst results
suggest that adoption may be adaptive for both the adoptive adult and the adopted
chick. This is because adopted chicks were more likely to �edge than their siblings
remaining in their own family and the �edging success of the adopter adults' own
chicks was higher than that of nonadoptive adults' chicks.
In my applied research I collect data on avocet breeding biology to �nd out
whether the current population increase in Hungary results from the reproductive
output of the Hungarian population or is maintained by an in�ux of birds from
coastal populations. I also use these data to design and implement e�ective
conservation measures by which to further enhance the Hungarian population of the
endangered Avocet. I successfully increased the hatching success of mainland nests
by erecting a fence to keep ground predators away. The �edging success of chicks
also increased after a predator control in the most a�ected areas. By providing
information about the timing of nesting to nature conservation authorities I assured
the successful breeding of one �fth of Hungary's avocet population on a �shpond
in 1999
