Repeated Human Intrusion and the Potential for Nest Predation by Gray Jays

2002 ◽  
Vol 66 (2) ◽  
pp. 372 ◽  
Author(s):  
Kevin J. Gutzwiller ◽  
Samuel K. Riffell ◽  
Stanley H. Anderson
Keyword(s):  
2008 ◽  
Vol 38 (7) ◽  
pp. 1974-1982 ◽  
Author(s):  
Randy G. Thompson ◽  
Ian G. Warkentin ◽  
Stephen P. Flemming

Predation rates on the eggs and young of forest-nesting songbirds typically rise in association with anthropogenic fragmentation, but predator responses depend on the spatial scale of disturbance, context, and predator assemblages present. For landscapes that are naturally fragmented, such as the boreal forest, our understanding of nest predation patterns associated with harvest may be further confounded by an additive response of nest predators to the loss of forest cover and the extension of habitat edges. We examined predation rates on artificial nests across a range of values for landscape metrics reflecting natural and anthropogenic forest fragmentation during two summers in boreal forest stands of western Newfoundland, Canada. Nest predation by gray jays ( Perisoreus canadensis (L.)) increased significantly in logged areas, and gray jay abundance was positively linked to increasing amounts of logged edge; however, there was no response to the extent of natural openings suggesting that nest predation by jays was additive in the presence of harvest-created openings. In contrast, neither mammalian nest predators nor the unidentified predators (responsible for the largest proportion of nest losses) showed any association with the landscape fragmentation metrics assessed. Year effects shown by the unidentified nest predator category did coincide with a marked increase in small mammal and Newfoundland marten ( Martes americana (Turton) subsp. atrata (Bangs)) populations during our study. Thus, we were able to identify an additive predation response to logging, but also that the activities of predators may vary over space and time and, in turn, may variably influence the success of songbirds nesting in forests fragmented by logging.


2003 ◽  
Vol 33 (5) ◽  
pp. 922-930 ◽  
Author(s):  
Marylène Boulet ◽  
Marcel Darveau ◽  
Louis Bélanger

The black spruce (Picea mariana (Mill.) BSP) forests of Quebec are often harvested according to a single-pass system where clearcuts are separated by 20- to 60-m-wide forest strips. Little is known about the suitability of these strips as habitats for breeding birds. We selected five nonriparian strips, five riparian strips, and five forest control sites located in a forested area of central Quebec. During 1997–1998, we monitored the predation of artificial bird nests baited with a common quail (Coturnix coturnix L.) egg and a plasticine egg and the breeding activity of adult songbirds in strips and controls. Artificial nest predation was high in all sites (72%). The most common predators were specialists of mature coniferous forests: gray jays (Perisoreus canadensis L.) and red squirrels (Tamiasciurus hudsonicus Erxleben). In forest-dwelling bird species, the number of breeding pairs was lower in strips than in controls. We conclude that the small number of forest-dwelling breeding birds observed in strips is not related to an increase in predation pressure following harvest of adjacent forests and that forest strips are not suitable breeding habitats for these species.


Ecography ◽  
2001 ◽  
Vol 24 (6) ◽  
pp. 742-750 ◽  
Author(s):  
Lena M. Eriksson ◽  
Lars Edenius ◽  
Veronika Areskoug ◽  
Dennis A. Meritt Jr

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser

Predation of offspring is the main cause of reproductive failure in many species, and the mere fear of offspring predation shapes reproductive strategies. Yet, natural predation risk is ubiquitously variable and can be unpredictable. Consequently, the perceived prospect of predation early in a reproductive cycle may not reflect the actual risk to ensuing offspring. An increased variance in investment across offspring has been linked to breeding in unpredictable environments in several taxa, but has so far been overlooked as a maternal response to temporal variation in predation risk. Here, we experimentally increased the perceived risk of nest predation prior to egg-laying in seven bird species. Species with prolonged parent-offspring associations increased their intra-brood variation in egg, and subsequently offspring, size. High risk to offspring early in a reproductive cycle can favour a risk-spreading strategy particularly in species with the greatest opportunity to even out offspring quality after fledging.


Author(s):  
Kristina Noreikienė ◽  
Kim Jaatinen ◽  
Benjamin B. Steele ◽  
Markus Öst

AbstractGlucocorticoid hormones may mediate trade-offs between current and future reproduction. However, understanding their role is complicated by predation risk, which simultaneously affects the value of the current reproductive investment and elevates glucocorticoid levels. Here, we shed light on these issues in long-lived female Eiders (Somateria mollissima) by investigating how current reproductive investment (clutch size) and hatching success relate to faecal glucocorticoid metabolite [fGCM] level and residual reproductive value (minimum years of breeding experience, body condition, relative telomere length) under spatially variable predation risk. Our results showed a positive relationship between colony-specific predation risk and mean colony-specific fGCM levels. Clutch size and female fGCM were negatively correlated only under high nest predation and in females in good body condition, previously shown to have a longer life expectancy. We also found that younger females with longer telomeres had smaller clutches. The drop in hatching success with increasing fGCM levels was least pronounced under high nest predation risk, suggesting that elevated fGCM levels may allow females to ensure some reproductive success under such conditions. Hatching success was positively associated with female body condition, with relative telomere length, particularly in younger females, and with female minimum age, particularly under low predation risk, showing the utility of these metrics as indicators of individual quality. In line with a trade-off between current and future reproduction, our results show that high potential for future breeding prospects and increased predation risk shift the balance toward investment in future reproduction, with glucocorticoids playing a role in the resolution of this trade-off.


2021 ◽  
pp. 1-11
Author(s):  
M. Soledad Vazquez ◽  
Lucía B. Zamora-Nasca ◽  
Mariano A. Rodriguez-Cabal ◽  
Guillermo C. Amico

2021 ◽  
Vol 60 ◽  
pp. 125970
Author(s):  
Angela J. Ferguson ◽  
Robert L. Thomson ◽  
Martha J. Nelson-Flower ◽  
Thomas P. Flower

Author(s):  
Julia Gómez-Catasús ◽  
Adrián Barrero ◽  
Margarita Reverter ◽  
Daniel Bustillo-de la Rosa ◽  
Cristian Pérez-Granados ◽  
...  

2007 ◽  
Vol 121 (2) ◽  
pp. 150
Author(s):  
Vanessa B. Harriman ◽  
Justin A. Pitt ◽  
Serge Larivière

Ground-nesting birds typically experience high predation rates on their nests, often by mammalian predators. As such, researchers and wildlife managers have employed numerous techniques to mitigate nest predation. We investigated the use of scents as repellents to deter predators from both artificial and natural ground nests. Survival rates of artificial nests did not differ among six groups of substances (Wald ?2 df = 5 = 4.53, P < 0.48); however the chronology of predation among groups differed. A commercial Coyote urine based deterrent (DEER-D-TERTM), human hair, and Worcestershire sauce were depredated faster than the control (F4,5 = 40.3, P < 0.001). Nest survival of natural nests differed among those groups tested (Wald ?2 df = 2 = 11.8, P < 0.005); the eight mothball treatment decreased survival (Wald ?2 df = 1 = 11.5, P < 0.005), which indicated that novel smells may attract predators or result in duck nest abandonment when coupled with natural duck scent. Chronologies of predation events among treatment groups were not different for natural nests (F2,3 = 1.9, P = 0.22). These findings indicate an interaction between novel scents and predator olfactory cues.


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