Snake slough in birds’ nests acts as a nest predator deterrent

ABSTRACTPredator-prey interactions are fundamental drivers of population dynamics, yet rarely are both predator and prey species simultaneously studied. Despite being significant, widespread avian nest predators, research on the ecology of Southeast Asian snakes in relation to birds remains scarce. The green cat snake (Boiga cyanea) is a primary nest predator, responsible for ≈24% of forest songbird depredation in Northeast Thailand. We explored both diurnal and nocturnal movements of 14 (5 male, 9 female) adult B. cyanea with radio-telemetry for an average of 68 ± 16 days per individual, between 21 October 2017 and 8 June 2019 in the dry evergreen forest of the Sakaerat Biosphere Reserve (SBR). We quantified area of space use (ha) and activity through motion variance (Ϭm2) during the study period using dynamic Brownian bridge movement models, and linked our findings to a simultaneously-run avian nest monitoring study, initiated in 2013 within the same forest fragment. On average, movements, space use and activity differed between males and females, and between the avian nesting and non-nesting seasons. Males moved 51.37 m/day farther than females. They used areas 15.09 ha larger than females, and their activity was 3.91 Ϭm2 higher than that of females. In general, individuals moved 50.30 m/day farther during the nesting season than the non-nesting season. The snakes used areas 9.84 ha larger during the nesting season than the non-nesting season, and their activity during the nesting season was 3.24 Ϭm2 higher than that during the non-nesting season. All individuals were exclusively nocturnal, moving throughout the night, and often descending from higher diurnal refugia (>2 m) to forage closer to the ground after sunset. Boiga cyanea activity followed a similar trend to that of the recorded nest depredations at SBR. Our study links snake activity to nest depredations in SBR. Our openly-available data may yield further insight when combined with other major avian nest predator species like the congeneric invasive brown tree snake (Boiga irregularis) on the island of Guam.

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Remotely sensed forest understory density and nest predator occurrence interact to predict suitable breeding habitat and the occurrence of a resident boreal bird species

Ecology and Evolution ◽

10.1002/ece3.6062 ◽

2020 ◽

Vol 10 (4) ◽

pp. 2238-2252

Author(s):

Julian Klein ◽

Paul J. Haverkamp ◽

Eva Lindberg ◽

Michael Griesser ◽

Sönke Eggers

Keyword(s):

Bird Species ◽

Remotely Sensed ◽

Breeding Habitat ◽

Forest Understory ◽

Nest Predator

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Nest-predator prevalence along a mountain birch - alpine tundra ecotone

Wildlife Research ◽

10.1071/wr11031 ◽

2011 ◽

Vol 38 (6) ◽

pp. 525

Author(s):

Åshild Ø. Pedersen ◽

Lasse Asmyhr ◽

Hans Christian Pedersen ◽

Nina E. Eide

Keyword(s):

Nest Predation ◽

Alpine Tundra ◽

Mountain Birch ◽

Pine Marten ◽

Willow Ptarmigan ◽

Generalist Species ◽

Management Actions ◽

Nest Predator ◽

Predation Rates ◽

Birch Forests

Context Nest predation is a major factor influencing life history and population dynamics of ground-nesting birds. The transitions between the northern boreal mountain birch forests and the low-alpine tundra are important habitats for the willow ptarmigan, Lagopus lagopus (Linnaeus, 1758). During the past decades, these landscapes have been extensively developed with cabin resorts in southern Norway, which has led to an increased number of roads and foot paths in relatively undisturbed habitats. Aims The aim of the present study was to investigate relative nest-predation rates in elevation gradients (ecotones) spanning from northern boreal mountain birch forests to low-alpine tundra in three locations with contrasting willow ptarmigan densities. Methods We conducted an artificial nest study by using baited track boards (n = 108). Track boards were placed along transects (200 m) in the following three habitat types: birch forest, edge habitat and low-alpine tundra. Predator prevalence was analysed in relation to study-design variables (location, habitat, study period) and the load of human infrastructure (i.e. distance to foot paths and roads), using generalised linear mixed-effect models assuming binomial distribution for the response variable. Key results Prevalence of avian predators was consistently high (range 38.2–85.3%), in contrast to much lower prevalence of mammalian predators (range 2.8–22.9%). Raven (Corvus corax) was the dominant nest predator, followed by hooded crow (C. cornix) and pine marten (Martes martes). Location, as contrasted by differences in willow ptarmigan density, was not significantly related to total relative predation rates. Species-specific predator prevalence was habitat specific and related to human infrastructure, but with opposite relative predation patterns between pine marten and raven. Hooded crow predation was similar across the ecotone and not related to human infrastructure. Conclusions Predator prevalence was habitat specific and affected by human infrastructure (distance to human foot paths). Our study confirmed that human activity might alter the predation rates by generalist species in these low-alpine environments. Implications We recommend that attractive willow ptarmigan habitat should be avoided when planning human infrastructure in alpine ecosystems. To reduce predation pressure in this ecosystem, it appears that generalist predators should be considered for management actions. Further research is needed to explain the underlying mechanism driving expansion of generalist species into alpine habitats. Such knowledge is also important in developing alternative management actions with focus other than predator control.

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Effects of forest management practices, weather, and indices of nest predator abundance on nest predation: A 12-year artificial nest study

Forest Ecology and Management ◽

10.1016/j.foreco.2016.02.006 ◽

2016 ◽

Vol 366 ◽

pp. 23-31 ◽

Cited By ~ 3

Author(s):

Gail Morris ◽

L. Mike Conner

Keyword(s):

Forest Management ◽

Nest Predation ◽

Management Practices ◽

Artificial Nest ◽

Forest Management Practices ◽

Predator Abundance ◽

Nest Predator

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The Raccoon Dog – an important new nest predator of Black-tailed Godwit in northern Germany

Wader Study ◽

10.18194/ws.00143 ◽

2019 ◽

Vol 126 (1) ◽

pp. 28-34 ◽

Cited By ~ 2

Author(s):

Volker Salewski ◽

Luis Schmidt

Keyword(s):

Raccoon Dog ◽

Northern Germany ◽

Nest Predator

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Is nest predator exclusion an effective strategy for enhancing bird populations?

Biological Conservation ◽

10.1016/j.biocon.2010.05.008 ◽

2011 ◽

Vol 144 (1) ◽

pp. 1-10 ◽

Cited By ~ 50

Author(s):

Rebecca K. Smith ◽

Andrew S. Pullin ◽

Gavin B. Stewart ◽

William J. Sutherland

Keyword(s):

Effective Strategy ◽

Bird Populations ◽

Predator Exclusion ◽

Nest Predator

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Does nest predator activity predict the location and survival of songbird nests in urbanizing landscapes?

The Condor ◽

10.1650/condor-17-23.1 ◽

2017 ◽

Vol 119 (4) ◽

pp. 745-760 ◽

Cited By ~ 2

Author(s):

Laura J Kearns ◽

Amanda D Rodewald

Keyword(s):

Nest Predator

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Experimentally induced antipredator responses are mediated by social and environmental factors

Behavioral Ecology ◽

10.1093/beheco/arz039 ◽

2019 ◽

Vol 30 (4) ◽

pp. 986-992 ◽

Cited By ~ 1

Author(s):

Frank Groenewoud ◽

Sjouke A Kingma ◽

Kat Bebbington ◽

David S Richardson ◽

Jan Komdeur

Keyword(s):

Predation Risk ◽

Nest Predation ◽

Bird Species ◽

Ecological Factors ◽

Antipredator Defense ◽

Trade Offs ◽

Future Reproduction ◽

Female Investment ◽

Predator Model ◽

Nest Predator

AbstractNest predation is a common cause of reproductive failure for many bird species, and various antipredator defense behaviors have evolved to reduce the risk of nest predation. However, trade-offs between current reproductive duties and future reproduction often limit the parent’s ability to respond to nest predation risk. Individual responses to experimentally increased nest predation risk can give insights into these trade-offs. Here, we investigate whether social and ecological factors affect individual responses to predation risk by experimentally manipulating the risk of nest predation using taxidermic mounts in the cooperative breeding Seychelles warbler (Acrocephalus sechellensis). Our results show that dominant females, but not males, alarm called more often when they confront a nest predator model alone than when they do so with a partner, and that individuals that confront a predator together attacked more than those that did so alone. Dominant males increased their antipredator defense by spending more time nest guarding after a presentation with a nest predator, compared with a nonpredator control, but no such effect was found for females, who did not increase the time spent incubating. In contrast to incubation by females, nest guarding responses by dominant males depended on the presence of other group members and food availability. These results suggest that while female investment in incubation is always high and not dependent on social and ecological conditions, males have a lower initial investment, which allows them to respond to sudden changes in nest predation risk.

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