Reproductive ecology of Brown-cheeked Laughing Thrushes (Garrulax henrici) in Tibet

Abstract

Most species in the genus Garrulax are found in subtropical or tropical areas of southeastern Asia, with few species adapted to temperate or high‐altitude climates. We examined the behavior and reproductive ecology of Brown‐cheeked Laughing Thrushes (G. henrici) from 1999 to 2005 at Xiongse Valley, Tibet. Cup‐shaped nests located 0.4–2.6 m above ground were found in 13 different species of plants, with roses and barberries the most common nest substrates. Laughing thrushes were socially monogamous and no territorial behaviors were observed. Egg‐laying was initiated in early May and ended by late August, with clutch sizes of either 2 or 3 eggs . Incubation started with the first egg being laid and the incubation period lasted 13–17 d . Young fledged at 14–16 d posthatching . Of 38 nesting attempts with known fates, at least one nestling hatched in 32 nests (84%) and at least one young fledged from 21 nests (55%). The mean number of fledglings per successful nest was 2.2 (range 1–3; N= 21 nests). Compared to lowland congeners, Brown‐cheeked Laughing Thrushes produced smaller clutches and larger eggs. Such differences suggest that laughing thrushes may invest more energy in fewer offspring at higher altitudes, as reported for other avian species and populations, and this may represent an adaptive response to high‐altitude environments where climates are harsh and food availability may be limiting.

Breeding Biology of the Snowy-cheeked Laughingthrush (Garrulax sukatschewi)

“…It was shorter than other common Garrulax species at similar latitudes, including Plain Laughingthrush (G. davidi) (late Apr-late Jul; Luo et al 1992) and Brown-cheeked Laughingthrush (G. henrici) (May-Aug; Lu et al 2008).…”

“…Field Procedures.-We located Snowy-cheeked Laughingthrush during four breeding seasons (Apr-Jul 2003, 2005, and 2008 and three non-breeding seasons (late Jul-mid Aug and Oct-Dec 2006, Sep 2007-Jan 2008 within 100 m of a 10.3-km long trail system by direct observations, and noted flock size and social interactions. We also played back calls, i.e., ''hwii-u, hwii-u'' (Collar et al 2007), of the birds and recorded their response.…”

Variation in egg and clutch size of the Black Redstart (Phoenicurus ochruros) at the northeastern edge of the Qinghai-Tibetan Plateau

“…Large eggs appear to have an advantage in harsh environments (Smith et al 1995;Fox and Czesak 2000). On the Tibetan Plateau, elevation affects the breeding ecology of birds (Lu et al 2007(Lu et al , 2008(Lu et al , 2010Du et al 2012Du et al , 2014 through the strong effects of temperature and rainfall, which also affect plant distribution and food availability. In our study area, temperature and rainfall were lower in 2008 than in 2009, suggesting that the climate in 2008 was harsher than in 2009 (Table 3).…”

“…Over the past half century, studies of the impact of weather on the population biology of birds represent a major field of study for ornithologists (Crick 2004). Climate not only affects the metabolism of birds but also directly or indirectly affects the reproduction of birds (Zhao et al 2002b;Crick 2004;Lu et al 2007Lu et al , 2008Lu et al , 2010Du et al 2012Du et al , 2014. On the other hand, birds possess several mechanisms by which they can adjust the magnitude and pattern of their breeding effort in relation to environmental conditions and to their own breeding condition (Slagsvold et al 1984).…”

“…The relations among avian life-history traits is also affected by climate change (Both and Visser 2005). We have only begun to scratch the surface, although ornithology has provided some of the best examples of the impact of recent climate changes on wildlife from around the world (Lu et al 2008). A range of intrinsic and extrinsic factors abound that could potentially inhibit adaptation to climate change.…”