Identification Of Nest Predators Research Articles

Diagnosing nest predators and anti-predator response of red wattled lapwing, Vanellus indicus (Boddaert, 1783)

Identification of nest predators and anti-predator behavior of Vanellus indicus (red wattled lapwings) were studied during two constitutive breeding periods (March-August) of 2018 and 2019. The study was performed along the river Ganges, Raebareli (Uttar Pradesh), India. The number of nesting pairs was counted by the line transect method and anti-predator responses were recorded by the focal sampling method. The nesting pairs varied significantly within and between study sites and years. A variety of predators (avian, mammalian and reptilian) were identified while some predators were designated in the unknown category. Sitting tight response was significantly different during the incubation period. The mobbing response, flying away and running away responses were significantly different during the post-incubation period. Circle noisily over the nests and alarm call were not significant between the two reproductive stages. We conclude that red wattled lapwings can differentiate among diverse predator species and adopt various anti-predator responses against them at different stages of their breeding cycle.

Parent-absent begging and the risk of nest predation

Despite the fact that parent-absent begging (PAB) has been studied as a communication tool during competition between nestlings for food or as a signal of need, its role in nest predation has been poorly investigated. In this study we examined whether the natural level of Common Cuckoo (hereafter “Cuckoo”) PAB increases the risk of artificial nest predation (n = 48) by using three types of experimental playback of parent-present begging (PPB) which differ in the presence or absence of additional PPB, PAB or periods of silence. Contrary to our predictions, we did not find a significant difference in daily survival rates between PPB + PAB vs. PPB + PPB nests or between PPB + PAB vs. PPB + silence nests, indicating that the natural level of Cuckoo PAB did not influence nest vulnerability to predation. Moreover, we did not find a significant difference between nests with any of the types of playback and completely silent control nests, suggesting that not only PAB, but also begging behaviour itself, does not present an important predation cost for nestlings, at least not in cases when nestlings beg at the natural level used in our experiment. As we filmed all experimental nests during their exposure to predators, we were able to show that eight of 20 filmed nest-predation events were caused by predators that never or rarely predate upon passerine nests. Excluding predation events by these unlikely predators, however, did not change our original results. Nonetheless, we advocate direct identification of nest predators to strengthen the interpretation of future studies on the predation cost of begging.

Predation of artificial bird nests in suburban gardens of KwaZulu-Natal, South Africa

As urbanization increases, the identification of nest predators becomes important for avian conservation and management of urban wildlife communities. We investigated bird nest predation using artificial nests in urban areas of the KwaZulu-Natal (KZN) Province of South Africa. From June 2013 through February 2014 we installed seventy-five artificial nests in 25 suburban gardens in the Ethekwini and Msunduzi municipalities of KZN. Euplectes spp. nests were used and baited with two quail-sized, hand-made, silicon eggs. These were placed in residential gardens and monitored by camera traps for 2-weeks in winter, spring and summer respectively. Generally bird nesting occurs throughout the year in KZN’s subtropical climate, with some avoidance during the autumn season. Therefore, experiments were not conducted during autumn, as fresh nests were not available for use. Overall the rate of predation on artificial nests was 25 % (n = 19), with vervet monkeys Ceropithecus aethiops pygerythrus predating 20 % (n = 17) of the nests while domestic cats Felis catus predated 3 % (n = 2) of nests. Nest predation was significantly higher in the winter season, with 79 % of depredations occurring in winter (n = 15), 16 % in spring (n = 3) and 5 % in summer (n = 1), and in areas with less canopy cover. Our results suggest that vervet monkeys may have a negative impact on nesting birds in urban environments, however, in order to assess the rate of predation experiments on natural nests coupled with information on fledgling success is deemed necessary to investigate avian population declines.

Mortality of Wood Warbler Phylloscopus sibilatrix nests in Welsh Oakwoods: predation rates and the identification of nest predators using miniature nest cameras

Capsule Predation was the main cause of nest failure, but predation rates have remained unchanged since the 1980s. Eurasian Jays Garrullus glandarius were the most common predator. Aims To quantify, and compare, nest predation rates for 1982–84 and 2009–11, and to identify predators of Wood Warbler Phylloscopus sibilatrix nests in Welsh oakwoods. Methods During 2009–11, 167 Wood Warbler nests were monitored and purpose-built miniature nest cameras deployed at 73 of them. Nest predation rates were compared with 67 nests monitored during 1982–84. Results Of 167 nests monitored from 2009 to 2011, 62 failed due to predation (32/73 camera nests, 30/94 non-camera nests), giving an overall Daily Survival Rate (DSR ± se) of 0.979 ± 0.003. This was not significantly different from the rate during 1982–84 (0.967 ± 0.006). In 2009–11, the DSR of nests declined temporally during the season at both the egg and chick stages. For chick stage nests, DSR varied annually and nonlinearly with age of nestlings. There was no evidence for an effect of cameras at either stage. Of 32 camera nests lost to predation, the predator was identified from 28, resulting in 30 predators being identified. There was one case of multiple predators at a single nest. The majority of nest predation was carried out by birds (28/30), predominantly Eurasian Jays (18/28), but also Common Buzzards Buteo buteo (5/28), Great Spotted Woodpeckers Dendrocopos major (3/28) and Eurasian Sparrowhawks Accipiter nisus (2/28). There was one predation by both a Eurasian Badger Meles meles and a Red Fox Vulpes vulpes. There were no records of Grey Squirrels Sciurus carolinensis depredating nests. Conclusions Nest predation rates were similar in both periods, suggesting that increased rates of nest predation have not been driving the decline of the Wood Warbler population in Wales. Deployment of nest cameras did not affect nest survival rates and were successful in identifying nest predators, the majority of which were avian, especially Eurasian Jays. Knowledge of the identity of nest predators can aid the development of conservation measures.

Identification of nest predators using continuous time-lapse recording in a New Zealand city

Predation of eggs and/or chicks is the main cause of nesting failure in birds. Nest predation has been studied in many habitats in New Zealand, but few studies have been conducted in urban ecosystems. Twenty-one nests of four bird species (blackbird [Turdus merula], song thrush [Turdus philomelos], fantail [Rhipidura fuliginosa], and silvereye [Zosterops lateralis]) were monitored over one breeding season in Hamilton using time-lapse recordings. Five predation events were filmed (two by cats [Felis catus], and three by ship rats [Rattus rattus]), 10 nests successfully fledged chicks and 6 nests failed owing to poor weather, desertion, or unknown events. Although the sample size was small, our data suggest that nesting success may be higher in urban Hamilton than in other unmanaged habitats where predation rates can exceed 80%. We recommend that future studies of nesting success in urban birds should also focus on the fates of fledglings, as anecdotal evidence suggested that predation rates may have been highest at this stage.

Nest-Site Selection and Nesting Success of Grey-Backed Thrushes in Northeast China

We identified microhabitat features affecting nest-site selection and examined nest-site characteristics associated with success for the Grey-backed Thrush (Turdus hortulorum) in the Dagang Forestry Farm, Jilin Province, northeast China. We collected data from 79 nests from April to August 2008. Twenty-nine nests (36.7%) were successful, 47 (59.5%) failed due to predation, and the rest were either destroyed by storms or abandoned. The overall daily survival rate (DSR) was 0.9563 ± 0.0072. Nest attempts beginning late in the breeding season were more likely to be depredated. Averaged DSR of laying and late nestling (days 7–12 after hatching) periods were higher than those of incubation and brooding (days 1–6 after hatching). We compared habitat variables between nest and random sites and assessed the effects of nest-location and nest-patch characteristics on DSR. Grey-backed Thrushes selected nest sites with shorter ground cover and a high density of small trees and shrubs. DSR was positively related to distance from the nest to the main stem of the nest tree and negatively correlated with horizontal exposure. Further research should focus on identification of nest predators, implications of nest exposure and begging calls on nesting success, and breeding habitat requirements at different spatial and temporal scales of Grey-backed Thrush in fragmented landscapes of northeast China.

Weak effect of edges on avian nesting success in fragmented and forested landscapes in Ontario, Canada

We studied the effects of anthropogenic edges on predation and parasitism of forest bird nests in an agriculturally fragmented landscape and a continuously forested landscape in Ontario, Canada. Nesting data were collected at 1937 nests across 10 species in the fragmented landscape from 2002–2008, and 464 nests across 4 species in the continuously forested landscape from 2006–2008. Brood parasitism only occurred in the fragmented landscape, and was positively related to the proportion of rural grassland and row crop habitats within 500-m of nests. Daily nest survival was negatively related to the density of roads within 500-m of nests in the fragmented landscape, but was not influenced by distance to anthropogenic edge in either landscape. Predation rates were higher in the fragmented landscape for Ovenbird and Rose-breasted Grosbeak nests, but did not differ between landscapes for Veery and American Redstart nests. Uniformly high predation in the fragmented landscape may be a result of (1) matrix predators that penetrate deep (>300 m) into the forest interior, or (2) the additive effect of forest-dependent and matrix-associated predators that results in high predation pressure in both edge and interior habitats. Further research focused on the identification of nest predators, their population dynamics, and habitat use is required to understand the underlying mechanisms leading to uniformly high nest predation in fragmented landscapes.

Identification of nest predators: a sampling perspective

Videotaping is currently recognized as the most reliable method of predator identification at active bird nests but it is relatively expensive and labour intensive. While the number of published studies has increased over the past 10 years, the mean sample size is not increasing. Thirty‐one case studies (n>5 events) reported 6–70 (median=22) predation events by 2–14 (6) species of predators. The number of predator species increased with a 0.50±0.09 (SE) power of sample size across studies (0.54±0.06 with the present study included). This relationship was consistent across single‐ and multi‐species studies and corresponded well with that found within the present 5‐year study (176 events, 20 species) where neither the annual nor the pooled‐sample species accumulation curve reached an obvious asymptote. The species accumulation curve was smooth and fell within the confidence limits of the rarefaction curve over the entire range of sample sizes, suggesting homogeneous sampling. In 31 case studies the dominant predator accounted for 21–96% (38%) of total predation and this proportion did not correlate with the sample size across studies. In this study the observed proportion fluctuated widely until the cumulative sample size reached about 50 records and stabilized thereafter at the final value of 37%. Because the regional pool of potential nest predators is usually high, a complete enumeration of the local predator community is difficult with an acceptable nest monitoring effort. Correct identification of the dominant predators is likely even with small samples, but quantification of their share is uncertain when based on <50 records. Researchers are encouraged to increase their sampling effort above the current level and to consider contingency of results upon sample size.

Predators of Spotted Flycatcher Muscicapa striata nests in southern England as determined by digital nest-cameras

Capsule Avian predators are principally responsible. Aims To document the fate of Spotted Flycatcher nests and to identify the species responsible for nest predation. Methods During 2005–06, purpose-built, remote, digital nest-cameras were deployed at 65 out of 141 Spotted Flycatcher nests monitored in two study areas, one in south Devon and the second on the border of Bedfordshire and Cambridgeshire. Results Of the 141 nests monitored, 90 were successful (non-camera nests, 49 out of 76 successful, camera nests, 41 out of 65). Fate was determined for 63 of the 65 nests monitored by camera, with 20 predation events documented, all of which occurred during daylight hours. Avian predators carried out 17 of the 20 predations, with the principal nest predator identified as Eurasian Jay Garrulus glandarius. The only mammal recorded predating nests was the Domestic Cat Felis catus, the study therefore providing no evidence that Grey Squirrels Sciurus carolinensis are an important predator of Spotted Flycatcher nests. There was no evidence of differences in nest survival rates at nests with and without cameras. Nest remains following predation events gave little clue as to the identity of the predator species responsible. Conclusions Nest-cameras can be useful tools in the identification of nest predators, and may be deployed with no subsequent effect on nest survival. The majority of predation of Spotted Flycatcher nests in this study was by avian predators, principally the Jay. There was little evidence of predation by mammalian predators. Identification of specific nest predators enhances studies of breeding productivity and predation risk.

Identification of Nest Predators at a Least Tern Colony in Southwestern Indiana

Abstract Nest predators commonly limit productivity of Least Tern (Sterna antillarum) breeding colonies in both natural and artificial habitats. In 2003 and 2004 we used remote still cameras aimed at model nests and remote video cameras aimed at occupied Least Tern nests to identify predators of Least Terns breeding at Gibson Lake, an artificial breeding area in southwestern Indiana, USA. At the primary breeding site, a narrow gravel dike that bisects Gibson Lake (center dike), Ring-billed Gulls (Larus delawarensis) were responsible for 100% and 75% of known predation events on model nests in 2003 and 2004, respectively. Throughout the 2004 breeding season, the proportion of model nests disturbed by Ring-billed Gulls on the center dike was strongly correlated with their numbers roosting on the center dike. We recorded predation by Ring-billed Gulls on six Least Tern chicks and two eggs in 2004 with remote video cameras. Our evaluation of the predator community at Gibson Lake strongly implicated Ring-bille...

Quail eggs, modelling clay eggs, imprints and small mammals in an Australian woodland

Artificial nests and eggs have become popular and useful tools for studying nest predation on birds. In particular, they may assist in the identification of nest predators. However, quail eggs commonly used in many nest-predation studies may exclude the detection of predation by small-mouthed mammals, which may not be able to break the eggshells as readily as eggs of small passerines. In this study captive Brown Antechinus (Antechinus stuartii) were given Japanese Quail eggs. They failed to break the shell, although they consumed the egg's contents if the shell had been broken for them. Field trials were conducted in a large woodland fragment on the New England Tableland, New South Wales, using clay and quail eggs to identify predators. Pied Currawongs (Strepera graculina), and possibly other birds, were found to be the most significant nest predators. Mammals were judged to play a comparatively small role. However, we detected large imprints in one modelling clay egg, which corresponded with Koala (Phascolarctos cinereus) incisors. In addition, we report that clay eggs soften at high temperatures, which may affect the size of a predator's imprint, and therefore cause its misidentification.

Comparison of mechanically egg-triggered cameras and time-lapse video cameras in identifying predators at Dusky Flycatcher nests

We compared the effectiveness and reliability of mechanically egg-triggered set-cameras and time-lapse video cameras in identifying nest predators at active Dusky Flycatcher (Empidonax oberholseri) nests in Siskiyou County, California. We monitored 72 active flycatcher nests using camera systems from 1998 to 2000. Nest abandonment, hatching success, and daily survival rate did not differ between camera systems. Set-cameras were less reliable than video systems in successfully recording predation events (45% versus 95%). The nest predator assemblage between camera types differed significantly with more avian predators (primarily raptors) recorded at video-monitored nests. This may have been due to the failure of hawks and owls to take the trigger egg at set-camera nests during the nestling stage. We did not find a strong association between the condition of the nest (disturbed or undisturbed) after the predation event and the identity of the predator (mammalian or avian). We also documented disruption of the nest by visitors other than the original predator. These observations suggest that identification of nest predators based on nest remains can be highly inaccurate. We recommend the use of videography for accurate identification of nest predators. Results from studies identifying predators with egg-triggered cameras should limit conclusions to the incubation stage.

Techniques for trapping and tracking stoats (Mustela erminea); a review, and a new system

ystematic direct observations of the small, fast‐moving, and wide‐ranging stoat are rarely practicable. The simplest indirect methods of observation are kill‐trapping, live‐trapping, and footprint recording. The data obtainable and the advantages and disadvantages of these methods are reviewed. Two new kinds of traps and a footprint recording system are described; they are especially suitable for use in rugged field conditions far from base facilities. When operated together in suitable habitat, these techniques can provide useful information on the population structure, feeding habits, and natural movements of stoats. Together or singly they also have potential as management tools, especially in identification of nest predators and in faunal surveys of islands.