Behavioral plasticity is not significantly associated with head volume in a wild Chestnut Thrush (Turdus rubrocanus) population

Abstract

Background: The drivers of intraspecific variation in behavioral plasticity are poorly known. A widely held hypothesis is that brain size is positively correlated with behavioral plasticity. Methods:A total of 71 Chestnut Thrushes (Turdus rubrocanus) were caught in the wild population. We quantified behavior plasticity of activity of individuals measured in the same cage across two contexts (common and with a novel object stimulation), using a random regression analysis. We then investigated whether head volume (a proxy for brain size) was associated with behavioral plasticity in activity level using Spearman rank-order correlation. Results:We found no significant evidence that activity plasticity was associated with relative head volume. There was no sex difference in head volume or in variance in head volume. Conclusions:We speculate that the absence of an association between brain volume and activity behavior plasticity may result from the inaccuracy of using external skull measurements to estimate brain size, or from a particular part of the brain being responsible for plasticity in activity level.

Potential cuckoo hosts have similar egg rejection rates to parasitized host species

“…In our study area, the Elliot's Laughingthrush and the White-bellied Redstart are parasitized by the Large Hawk Cuckoo and the Common Cuckoo, respectively (Hu et al 2013a, b). However, field observations have found no evidence of cuckoo parasitism in the Chestnut Thrush or the Chinese Thrush (Zhao and Sun 2016;Hu et al 2017). Our results show that the Chestnut Thrush has a moderate egg rejection ability, which is similar to results from European studies of the Song Thrush and the Blackbird (Grim and Honza 2001).…”

“…There is limited data on the reproduction of Chinese Thrushes (Liu et al 2003). There have been no reports of cuckoo parasitism in the above two thrush species (Zhao and Sun 2016).…”

“…The Chestnut Thrush (Turdidae: Passeriformes), has a medium-sized body (23-28 cm, 85-120 g; Zhao 2001), and is distributed throughout the Indian subcontinent, the Indochinese Peninsula, as well as the southwest and southeast coastal areas of China (Collar 2005). In the study area, the Chestnut Thrush is one of the most common bird species, mainly inhabiting montane broadleaf forests and mixed coniferous forests at an altitude of 2000-3500 m (Zhao and Sun 2016). Its breeding season is from April to August, and nesting starts from late April to early May.…”

Nestling discrimination and feeding habits during brooding of Chestnut Thrushes

“…The Chestnut Thrush belongs to genus Turdus, in family Turdidae and order Passeriformes, which is of medium size and distributed throughout the Indian subcontinent, the Indochina Peninsula, and the southwest and southeast areas of China (Collar 2005). Chestnut Thrushes are one of the most abundant bird species in our study area, mainly inhabiting montane broad-leaved forests as well as coniferous and broad-leaved mixed forests (Zhao and Sun 2016) at an altitude of 2000-3500 m. The breeding period is from April to August, and its nests built from late April to early May, which are in the shape of an open cup at a height of 1-3 m from the ground with poor concealment (Hu et al 2017). Nests weigh around 250 g with an inner diameter of 100 mm and an outer diameter of 140 mm, with a cup depth of approximately 62 mm.…”

Comparison of breeding strategies of two sympatric thrush species in an alpine environment

“…Although Chestnut Thrush is a common species, few people have published about its reproductive ecology before, and there are some reports about it in Lianhua Mountain, Gansu Province. Nest site characteristics and nest success (Zhao and Sun, 2018), egg rejection and recognition mechanisms (Yi et al, 2020b), nestling discrimination and feeding habits during brooding (Yi et al, 2020a), behavioral plasticity in relation to head volume (Zhao and Sun, 2016), and Parental attendance reduce nest predation during the incubation period (Hu et al, 2017), and brief field observations describing the breeding habits of the Chestnut Thrush in Wanglang Nature Reserve, Sichuan (Zhang et al, 1986), while more detailed studies on the breeding biology of the Chestnut Thrush are less available. There is little research on the reproductive habits of Kessler's Thrush, only Yang et al (2012) and Gao et al (2022) have reported on the reproductive habits of Kessler's Thrush, lacking detailed reproductive biology information (Yang et al, 2012;Gao et al, 2022).…”