Edge effects on survival and behaviour of juvenile red squirrels (Tamiasciurus hudsonicus)

2002 ◽  
Vol 80 (6) ◽  
pp. 1038-1046 ◽  
Author(s):  
Elizabeth M Anderson ◽  
Stan Boutin
Keyword(s):  
Predation Risk ◽  
Edge Effects ◽  
Nest Predation ◽  
Survival Rates ◽  
Forest Edge ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrels ◽  
Emergence Period ◽  
High Predation ◽  
Survival Differences

Much research has examined parasitism and predation rates on avian nests within the context of edge effects. Few studies, however, have considered the influence that behavioural compensation for high predation risk may have on subsequent survival rates and edge effects. We attempted to determine whether juvenile red squirrels (Tamiasciurus hudsonicus) experience edge effects by comparing the survival and behaviour of individuals born along a forest edge with those of individuals born in the forest interior. A combination of telemetry, direct observation, and livetrapping was used to determine the fate of juveniles born during the summers of 1987 through 1998 and the behaviour of juveniles born during the summers of 1997 and 1998 in Kluane, Yukon. There were no differences in survival between edge and interior juveniles from birth to emergence but there was a trend towards higher survival rates for edge juveniles from emergence to weaning. Behavioural differences between edge and interior juveniles were consistent with these survival differences: edge juveniles spent less time travelling and foraging and more time resting near the time of weaning than did interior juveniles. Edge and interior mothers differed little behaviourally during the early emergence period. The significant differences in juvenile behaviour which we found suggest that behaviour may indeed moderate differences in predation risk between edge and interior habitats and thus should be considered in other studies that examine the influence of edges on survival or nest predation.

A meta-analysis of tropical forest edge effects on bird nest predation risk:

2013 ◽  
Vol 159 ◽  
pp. 382-395 ◽  
Author(s):  
Daniela Vetter ◽  
Gerta Rücker ◽  
Ilse Storch
Keyword(s):  
Tropical Forest ◽  
Predation Risk ◽  
Edge Effects ◽  
Nest Predation ◽  
Meta Analysis ◽  
Forest Edge ◽  
Bird Nest

scholarly journals Do Repugnant Scents Increase Survival of Ground Nests? A Test with Artificial and Natural Duck Nests

2007 ◽  
Vol 121 (2) ◽  
pp. 150
Author(s):  
Vanessa B. Harriman ◽  
Justin A. Pitt ◽  
Serge Larivière
Keyword(s):  
Human Hair ◽  
Nest Predation ◽  
Survival Rates ◽  
Olfactory Cues ◽  
Artificial Nests ◽  
Treatment Groups ◽  
Mammalian Predators ◽  
High Predation ◽  
Ground Nesting ◽  
Predation Rates

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.

Predation on different-sized quail eggs in an artificial-nest study in western Newfoundland

1999 ◽  
Vol 77 (7) ◽  
pp. 1170-1173 ◽  
Author(s):  
Keith P Lewis ◽  
William A Montevecchi
Keyword(s):  
Japanese Quail ◽  
Small Mammals ◽  
Nest Predation ◽  
Egg Size ◽  
Tamiasciurus Hudsonicus ◽  
Buffer Strips ◽  
Artificial Nest ◽  
Red Squirrels ◽  
Artificial Nests ◽  
Riparian Buffer Strips

In artificial-nest studies, Japanese Quail (Coturnix japonica) eggs have been used as surrogates for passerine eggs, although small mammals that prey on passerine eggs may be unable to consume Japanese Quail eggs. To determine the influence of egg size on nest predation in different landscapes on insular Newfoundland, we placed either a Japanese Quail egg or a smaller Chinese Painted Quail (Xexcalfactoris chinensis) egg in artificial ground nests along lakeshore forest edges and along riparian buffer strips. Clay eggs were used to identify nest predators. Levels of predation on nests with Japanese Quail and Chinese Painted Quail eggs were similar. Based on clay eggs, predation was attributed to red squirrels (Tamiasciurus hudsonicus), and we found no evidence that smaller mammals preyed on artificial nests. We conclude that the Japanese Quail egg is acceptable for use in artificial-nest studies in Newfoundland, and we discuss the implications of egg size and small mammals in nest-predation experiments.

scholarly journals A Possible Role for Red Squirrels in Structuring Breeding Bird Communities in Lodgepole Pine Forests

The Condor ◽  
2006 ◽  
Vol 108 (1) ◽  
pp. 232-238 ◽  
Author(s):  
Adam M. Siepielski
Keyword(s):  
Nest Predation ◽  
Pinus Contorta ◽  
Lodgepole Pine ◽  
Bird Communities ◽  
Pine Forests ◽  
Tamiasciurus Hudsonicus ◽  
Breeding Bird ◽  
Bird Abundance ◽  
Red Squirrels ◽  
Cavity Nesters

Abstract Nest predation is thought to play an important role in structuring certain breeding bird communities. One potential consequence of nest predation is lower recruitment in breeding birds, which may be manifested as lower breeding bird abundance. Lodgepole pine (Pinus contorta ssp. latifolia) forests east and west of the Rocky Mountains became isolated following glacial retreat 12 000 years ago and differ in whether or not red squirrels (Tamiasciurus hudsonicus), which are a key nest predator, are present. Breeding bird abundance in lodgepole pine forests was compared between four ranges with red squirrels and four ranges without red squirrels. Species grouped into canopy and understory nesting guilds were, on average, two and three times more abundant, respectively, in forest ranges without red squirrels than in ranges with red squirrels; no statistically significant differences were found for midstory, ground, or cavity nesters. These results suggest that geographic variation in the presence or absence of red squirrels is likely important in structuring breeding bird communities in lodgepole pine forests across the landscape.

Edge effects on nest predators in two forested landscapes

2004 ◽  
Vol 82 (12) ◽  
pp. 1943-1953 ◽  
Author(s):  
Michelle L Smith
Keyword(s):  
Species Richness ◽  
Edge Effects ◽  
Spatial Scales ◽  
Forest Edge ◽  
Tamiasciurus Hudsonicus ◽  
Brood Parasite ◽  
Camera Systems ◽  
Total Species Richness ◽  
Edge Response ◽  
Nest Predators

Few studies have systematically examined edge effects on nest predators, although many invoke these processes as potential mechanisms for decreased nesting success of songbirds. Species richness and relative abundance of avian and mammalian nest predators were compared between forest edge and interior in two landscapes, Allegan State Game Area and Fort Custer Training Center (FCTC), in southwest Michigan. One avian predator, the American crow (Corvus brachyrhynchos Brehm, 1822), was more abundant at edges than forest interior at FCTC; however, other predators did not demonstrate an edge response. Abundance of the brood parasite (Molothrus ater (Boddaert, 1783)) was greater at edges in FCTC. Overall abundance was higher at FCTC in both years; however, this could not be attributed to a greater extent of fragmentation. Total species richness for both landscapes did not differ between edge and interior. Remote-camera systems captured three predation events, two involving red squirrels (Tamiasciurus hudsonicus (Erxleben, 1777)) and one involving a blue jay (Cyanocitta cristata (L., 1758)). Vegetation characteristics were similar between edge and interior sites, which suggests that vegetation structure did not influence edge response. The variability in response indicates a need to assess patterns of predator distributions through long-term studies at multiple spatial scales.

Nest predation and breeding activity of songbirds in riparian and nonriparian black spruce strips of central Quebec

2003 ◽  
Vol 33 (5) ◽  
pp. 922-930 ◽  
Author(s):  
Marylène Boulet ◽  
Marcel Darveau ◽  
Louis Bélanger
Keyword(s):  
Nest Predation ◽  
Black Spruce ◽  
Bird Species ◽  
Breeding Birds ◽  
Tamiasciurus Hudsonicus ◽  
Red Squirrels ◽  
Pass System ◽  
Breeding Activity ◽  
Gray Jays ◽  
Riparian Strips

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.

No evidence of short-term effects of clear-cutting on artificial nest predation in boreal mixedwood forests

1999 ◽  
Vol 29 (12) ◽  
pp. 1900-1910 ◽  
Author(s):  
Susan E Cotterill ◽  
Susan J Hannon
Keyword(s):  
Populus Tremuloides ◽  
Nest Predation ◽  
Tamiasciurus Hudsonicus ◽  
Forest Patches ◽  
Red Squirrels ◽  
Artificial Nests ◽  
Clear Cutting ◽  
Mixedwood Forests ◽  
Continuous Forest ◽  
Predator Abundance

We examined whether nest predation in unharvested blocks of trembling aspen (Populus tremuloides Michx.) would increase when adjacent stands were clearcut in the boreal mixedwood forest of Alberta, in 1993, 1994, and 1998. Artificial nests placed on the ground and in shrubs were baited with Chinese painted quail (Coturnix chinensis L.) and plasticine eggs, which along with cameras, were used to identify nest predators. Fragmented sites were isolated from continuous forest by clear-cutting in 1994, while control sites remained unfragmented. Overall, predation on ground and shrub nests did not increase in isolated forest patches post-harvest (p = 0.056 and p = 0.085, respectively), nor was there a consistent effect of distance from a clearcut edge (p >= 0.050). Predation on ground nests was higher in 1994 and 1998 compared with 1993 levels (p < 0.001), while predation on shrub nests remained relatively constant over the 3 years (p >= 0.073). Mice, voles, and red squirrels (Tamiasciurus hudsonicus Erxleben) were the main identified predators of ground and shrub nests, respectively. Probability of nest predation could not be consistently predicted by nest site vegetation or adjacent land cover, but was related to predator abundance. However, neither predators nor songbirds congregate at recent clearcut-forest edges, and we conclude that elevated nest predation caused by clear-cutting may not occur in the boreal mixedwood, at least not at current levels of harvest and within 5 years of clear-cutting.

Elevated nest predation risk promotes offspring size variation in birds with prolonged parental care.

2019 ◽  
Author(s):  
Gretchen F. Wagner ◽  
Emeline Mourocq ◽  
Michael Griesser
Keyword(s):  
Predation Risk ◽  
Reproductive Cycle ◽  
Perceived Risk ◽  
Nest Predation ◽  
Bird Species ◽  
Size Variation ◽  
Egg Laying ◽  
Offspring Size ◽  
Natural Predation ◽  
Risk Spreading

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.

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