Nesting near road edges improves nest success and post-fledging survival of White-rumped Shamas (Copsychus malabaricus) in northeastern Thailand

Abstract

Road edges in the temperate zone often negatively affect reproductive success, post-fledging survival, and dispersal of forest birds through processes associated with edge habitats. This pattern is less clear in the tropics due to a lack of studies using natural nests and radio-tagged fledglings as well as an almost complete absence of information on nest and fledgling predators. We investigated the influence of road edge on nest success, post-fledging survival, and dispersal of White-rumped Shama (Copsychus malabaricus) in a dry evergreen forest in northeastern Thailand. One hundred nest boxes were placed in forest interior (≥1,000 m from edge of a 5-lane highway) and 100 near forest edge (≤200 m) to assess nesting success. We radio-tracked 50 fledglings from these boxes, 25 each for edge and interior, for 7 weeks after fledging. Nest success and post-fledging survival were 11.6% and 23.6% higher at the edge versus the interior. Predation had the strongest influence on survival, accounting for 100% of nest and 94% of fledgling mortality. Fledglings used locations with denser understory vegetation cover relative to the available habitat, probably to reduce predation risk. Green cat snake (Boiga cyanea) and northern pig-tailed macaque (Macaca leonina), which likely prefer forest interiors over edges, were the primary predators of nests and fledglings in this landscape. There were no significant differences in timing of dispersal and dispersal distance or dispersal direction in relation to proximity to edge. Our results suggest that the impacts of edge effects on the reproductive success of birds appear to be strongly dependent on the habitat preferences of locally dominant predators. Further research will be needed to identify key predators and broadly assess their foraging behaviors in individual landscapes.

Mechanistic home range analysis reveals drivers of space use patterns for a non‐territorial passerine

“…The BIC values can be compared with the previous Model 4 (BIC = 14,297) using the last column in the taxa (e.g. Angkaew, Sankamethawee, Pierce, Savini, & Gale, 2019;Hansen, Sato, Michael, Lindenmayer, & Driscoll, 2019;Valentine, Apol, & Proppe, 2019). Conversely, other studies have reported the reverse pattern, with lower predation risk in edge habitats relative to core sites (e.g.…”

Effects of off-highway vehicles on avian abundance and diversity in a designated vehicular recreation area

“…However, it is not unprecedented for a bird species to benefit from being close to disturbance. The White-rumped Shama (Copsychis malabaricus) had both higher nest success and postfledging survival at nest sites nearer to road edge in Asia (Angkaew et al 2019). Although we did not study nesting, the White-rumped Shama study suggests that birds in our study area could also receive some fitness benefit from nesting closer to disturbance.…”

Arboreal aperitifs: Space use and activity of a major songbird nest predator in a tropical Thailand forest

“…Our study attempts to gain insight into the free-ranging and foraging ecology of this primary nest predator as a follow up to the research by Khamcha et al . (2018) and Angkaew et al . (2019) within the same study site.…”

“…(2018) reported that snakes were responsible for 34% of predation events on 287 monitored nests. More specifically, data suggest that Green cat snake Boiga cyanea is the dominant snake nest predator in the seasonally wet and dry evergreen forests of Northeast Thailand (Angkaew et al, 2019; Khamcha et al, 2018; Khamcha and Gale, 2020; Pierce et al, 2020). Despite the evidence of Southeast Asian snakes– particularly that of nocturnal, arboreal species (Donald et al, 2009; Pierce et al, 2020; Pierce and Pobprasert, 2013)– as nest predators, little to no research exists assessing their movement ecology.…”