You have full access to this open access article. Offspring desertion by a single parent, mainly the female, occurs in many charadriiform birds. According to the differential parental capacity hypothesis DPCH , females are more likely to desert, since they may be in poorer body condition than males as a consequence of egg-laying costs. This study investigated the body condition of male and female Whiskered Terns. In this species half of females desert during the chick-rearing period, the remainder during the post-fledging period.
Body condition was investigated during the late incubation and early chick-rearing phases during the biparental care period in: 1 females that deserted during the chick-rearing period, 2 females that did not desert during this time, 3 males deserted by females, and 4 males not deserted by females. After hatching, body condition was lower in both deserting and non-deserting females caught later.
Among males whose females stayed, body condition remained nearly stable, whereas the body condition of males whose females deserted was lower the later they were caught. These results tally only partially with the DPCH: the pattern of parental body condition changes during breeding is apparently more complex than assumed by the DPCH and the cost of egg laying may be lower than suggested.
Desertion by Whiskered Tern females is better explained by the sex role differences in parental care. Furthermore, the deserter could benefit by departing on migration earlier e. Gratto-Trevor ; Currie et al. Ezaki ; Urano ; Kloskowski ; Hemborg ; Mumme It has been shown that the mate continuing parental care increases provisioning rates, in this way compensating the lack of the mate.
One important factor which could influence desertion is body condition Erckmann ; McNamara and Houston ; Webb et al. However, the relationship between natural desertion and body condition has rarely been studied. The principal hypothesis explaining the relationship between natural parental desertion and body condition is the differential parental capacity hypothesis hereafter DPCH , formulated for Charadriiformes by Erckmann In this group of birds, the offspring are more often deserted by females than by males, but in some species both males and females are known to desert Warriner et al.
