Time Spent With Parents Varies With Early-Life Condition, but Does Not Predict Survival or Sociality of Juvenile Hihi

Abstract

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 3 s to 10 min). 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.

Consequences of space sharing on individual phenotypes in the New Zealand hihi

“…Individuals sharing an important part of their home-range are more likely to interact with each other than with non-neighbouring individuals. Copying other individuals' behaviour is frequently observed in wild animal populations (Dugatkin 1996;Laland 2004), including the hihi (Franks and Thorogood 2018;Franks et al 2019), and can result in the rapid spread of specific behavioural phenotypes, ultimately increasing behavioural heterogeneity between groups. For example, variation in behaviour can be observed locally for traits such as foraging (Coolen et al, 2003), parental care (Champagne, 2008), mate and habitat choice (Dugatkin 1996;Doligez et al 2002) or predator evasion (Halloy et al 2007).…”

“…Zealandia sanctuary shelters a highly heterogeneous landscape composed of intact native bush, planted exotic trees and regenerating forest patches (Starbridge 2009). Previous quantitative genetic studies on another hihi population have demonstrated low narrow-sense heritability for morphological and life history traits despite large phenotypic variation between birds (de Villemereuil et al, 2018a;de Villemereuil et al, 2019), reinforcing the need to explore other forces generating differences between individuals such as the influence of the spatial structure of the population (Franks et al 2019). First, we studied dispersal patterns of hihi across Zealandia's landscape in order to understand how birds establish their home-range.…”

Foraging behaviour alters with social environment in a juvenile songbird

“…Overall, these findings indicate that young passerines may not retain specific preferences from early-life exposure to stimuli with parents. This could be due to the short period of dependency found in many Passeridae (for example, hihi spend approximately two weeks in the natal territory [51]) in comparison to other species which have longer post-fledging association with parents (e.g. : [17]).…”