Published in: Frontiers in Ecology and Evolution
Authors: Victoria R. Franks, Mhairi McCready, James L. Savage and Rose Thorogood
Many young birds die soon after ﬂedging, as they lack the skills to ﬁnd food and avoid predation. Post-ﬂedging parental care is assumed to assist acquisition of these vital skills. However, we still lack empirical examples examining the length of time ﬂedglings spend with parents, how they associate during this critical time, or whether such variation in the ﬂedgling dependency period has consequences for the survival and behaviour of young as they navigate their ﬁrst year of independent life. Here, we make use of observations and radio frequency identity (RFID) logs of visits to supplementary feeding stations to investigate how condition of ﬂedgling hihi (stitchbird, Notiomystis cincta), a New Zealand passerine, predicts dispersal behaviour and tendency to follow parents during their 2 week post-ﬂedging dependence period. We ﬁnd that thinner ﬂedglings followed their parents more closely in time when visiting feeding stations, compared to fatter siblings (all following ranged from 3s to 10min). However, broods in poorer condition tended to disperse from the natal territory up to 6.5 days earlier than broods of fatter ﬂedglings (all dispersed within 14 days). Our results did not ﬁnd that sociality or survival during the ﬁrst year of life differed depending on variation in ﬂedgling behaviour; neither following parents closely nor dispersing later predicted each bird’s number of associates (degree), or survival over winter. These results suggest that ﬂedglings may be able to compensate for early differences in condition with behaviour, either during the post-ﬂedging dependence period or when independent.
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