Songbird parents coordinate offspring provisioning at fine spatio‐temporal scales

Abstract

For parents, rearing offspring together is far from a purely cooperative exercise, as a conflict of interest (‘sexual conflict’) exists over their optimum level of care. Recent theory emphasizes that sexual conflict can be evolutionarily resolved, and complete parental cooperation can occur, if parents directly respond (‘negotiate’) to each other and coordinate their level of care. Despite numerous experiments showing that parents are responsive to each other, we still lack empirical evidence of the behavioural mechanisms by which this negotiation occurs. In this study, we investigated the spatio‐temporal coordination of parental provisioning behaviour as a possible mechanism of negotiation over parental care. We deployed an automated radiotracking technology to track the provisioning activity of wild great tit Parus major pairs during chick rearing. Our analyses represent the first detailed spatial and temporal description of foraging coordination in songbird parents in a natural context. We demonstrate that the foraging behaviour of the two parents is highly coordinated in space and time, with parents changing their foraging locations in conjunction with their partners' movements. Therefore, foraging coordination could be a mechanism by which parents directly monitor and respond to each other's level of investment.

Sex ratios and the city: Secondary offspring sex ratios, parental corticosterone, and parental body condition in an urban-adapted bird

“…Ouyang et al (2014) also found that the difference in baseline CORT was positively related to the difference in feeding rate. This finding supports the possibility that parents with similar levels of investment may be able to coordinate their care better and reduce sexual conflict between the parents (Baldan and Van Loon, 2022). This increased coordination should lead to 10.3389/fevo.2022.894583 increased synchronicity-regardless of whether CORT levels are similarly high or low-and higher provisioning rates (Bebbington and Hatchwell, 2016), thus increasing fledging success.…”

Parental provisioning is weakly age‐dependent and heritable in a small passerine

“…Until recently, it was challenging to obtain such high-quality data in a sufficient quantity, especially for forest species, which are difficult to observe while foraging. Fortunately, new technologies such as accelerometers (Lok et al 2023), radars (Brebner et al 2021), video traps (Surmacki & Podkowa 2022), radiofrequency identification readers (Iserbyt et al 2018) and automatic radio-tracking systems (Baldan & van Loon 2022) can facilitate gathering both high-quality and high-quantity data needed for further development of the field (Williams & Fowler 2015). Our study adds to the case for collecting these data, as provisioning rates were highly labile and sensitive to many external and internal factors.…”

Age-specificity in territory quality and spatial structure in a wild bird population

“…Additionally, increased familiarity between adult territorial neighbours may reduce competition associated with foraging (Grabowska-Zhang et al 2012b; Gokcekus et al 2023), or even promote joint benefits such as nest defence (Grabowska-Zhang et al 2012a), thus favouring closer breeding between adults. Recent advances in tracking technology of passerine foraging behaviour (Baldan and van Loon 2022) might advance insight into whether competition is reduced among older familiar neighbours by assessing evidence for increased coordination during foraging compared to unfamiliar neighbours.…”

“…Previous research in this system has assessed age-specificity in nest-site visitation patterns prior to breeding in terms of the number and spatial clustering of nest-boxes visited (Firth et al 2018). Thus, future work could incorporate such techniques with advances in the tracking of movement (Levin et al 2015; Baldan and van Loon 2022) and other defence behaviour (Merino Recalde 2023) to advance our understanding on the temporal scale at which individuals interact during territorial behaviour before breeding, how this is affected as territories are gradually occupied prior to the spring, and age-specific variation in this.…”