Nest Failure Research Articles

Nesting success of Turdus grayi (Passeriformes: Turdidae) at "El Zapotal" Recreational Ecological Preserve, Chiapas, Mexico.

Nesting success has been a surrogate to assess environmental changes that affect the reproductive success of birds, and to analyze changes that influence natality. We analyzed the nesting success of Turdus grayi at El Zapotal Recreational Ecological Preserve, Central Chiapas. During the 2015 breeding season, we intensively searched for active nests and evaluated habitat characteristics. We located a total of 56 nests of which 27 (48.2 %) were successful and 29 (51.7 %) were unsuccessful. Most unsuccessful nests (19) were depredated, while 8 (27.6 %) were abandoned and 2 (6.9 %) parasitized. Nesting success was 46 %. Depredation was the main mechanism of nest failure, mostly during incubation. We identified operating variables at site and patch scales. Through analysis of binary logistic regression models for each scale, we predicted which variables increased the probability of nesting success. We also performed a multivariate logistic regression analysis to rule out possible interactions among variables. At nest scale we found that nest height, ranging 4.2 - 5.1 m had increased nesting success, while at patch scale, the probability of nest success was greater at sites with a tree density ≥ 12. Our results indicated that the probability of nesting success did not show a relationship between scales. We suggest a decoupling between scales and mechanism. Thus, habitat changes occurring at local scale did not seem to interfere with the patch scale. Also, our results showed that variation in characteristics at nest scale could also influence depredation, when depredation had been presented at random, since nests with medium and high probability of being successful, failed also for this reason. Thus, in order to understand the factors, mechanisms and life history characteristics influencing nesting success, we suggest that in addition to the environmental variables, future studies should also consider the bird nesting behaviour.

Éxito de anidación de Turdus grayi (Passeriformes: Turdidae) en el Centro Ecológico Recreativo “El Zapotal”, Chiapas, México.

Nesting success has been a surrogate to assess environmental changes that affect the reproductive success of birds, and to analyze changes that influence natality. We analyzed the nesting success of Turdus grayi at "El Zapotal" Recreational Ecological Preserve, Central Chiapas. During the 2015 breeding season, we intensively searched for active nests and evaluated habitat characteristics. We located a total of 56 nests of which 27 (48.2 %) were successful and 29 (51.7 %) were unsuccessful. Most unsuccessful nests (19) were depredated, while 8 (27.6 %) were abandoned and 2 (6.9 %) parasitized. Nesting success was 46 %. Depredation was the main mechanism of nest failure, mostly during incubation. We identified operating variables at site and patch scales. Through analysis of binary logistic regression models for each scale, we predicted which variables increased the probability of nesting success. We also performed a multivariate logistic regression analysis to rule out possible interactions among variables. At nest scale we found that nest height, ranging 4.2 - 5.1 m had increased nesting success, while at patch scale, the probability of nest success was greater at sites with a tree density ≥ 12. Our results indicated that the probability of nesting success did not show a relationship between scales. We suggest a decoupling between scales and mechanism. Thus, habitat changes occurring at local scale did not seem to interfere with the patch scale. Also, our results showed that variation in characteristics at nest scale could also influence depredation, when depredation had been presented at random, since nests with medium and high probability of being successful, failed also for this reason. Thus, in order to understand the factors, mechanisms and life history characteristics influencing nesting success, we suggest that in addition to the environmental variables, future studies should also consider the bird nesting behaviour.

Predators of bird nests in the Neotropics: a review

Predation is the main cause of nest failure among birds and, therefore, a strong selective agent. To fully understand patterns of nest predation, determining the identities of nest predators is crucial. Information about nest predators in the Neotropics, however, is largely anecdotal and not easily accessible in the literature. Our objective was to search the literature and compile a list of the known predators of nests in the Neotropics. We identified 256 species belonging to 67 families of birds, reptiles, mammals, and arthropods as nest predators. Families with at least 10 species of identified nest predators included Colubridae, Accipitridae, Corvidae, Ramphastidae, Falconidae, Furnariidae, Icteridae, and Didelphidae. Species in the first five of these families, plus the family Cebidae, predated nests of at least 30 species of birds. Many species not included on our list are also likely nest predators, e.g., 79 species identified as nest predators in the Nearctic that also occur in the Neotropics, but have not yet been confirmed as predators there. Increased use of video technology in the future should lead to an increase in the numbers of nest predators identified, particularly those that are nocturnal. By determining which species on our list occur in a given study area, researchers can now consider the likely nest predators in their study areas when designing hypotheses and conservation plans.

Daily Survival Rate and Habitat Characteristics of Nests of Wilson's Plover

Abstract We assessed habitat characteristics and measured daily survival rate of 72 nests of Charadrius wilsonia (Wilson's Plover) during 2012 and 2013 on South Island and Sand Island on the central coast of South Carolina. At both study areas, nest sites were located at slightly higher elevations (i.e., small platforms of sand) relative to randomly selected nearby unused sites, and nests at each study area also appeared to be situated to enhance crypsis and/or vigilance. Daily survival rate (DSR) of nests ranged from 0.969 to 0.988 among study sites and years, and the probability of nest survival ranged from 0.405 to 0.764. Flooding and predation were the most common causes of nest failure at both sites. At South Island, DSR was most strongly related to maximum tide height, which suggests that flooding and overwash may be common causes of nest loss for Wilson's Plovers at these study sites. The difference in model results between the 2 nearby study sites may be partially due to more-frequent flooding at ...

Factors that influence vital rates of Seaside and Saltmarsh sparrows in coastal New Jersey, USA.

As saltmarsh habitat continues to disappear, understanding the factors that influence saltmarsh breeding bird population dynamics is an important step for the conservation of these declining species. Using five years (2011 - 2015) of demographic data, we evaluated and compared Seaside (Ammodramus maritimus) and Saltmarsh (A. caudacutus) sparrow apparent adult survival and nest survival at the Edwin B. Forsythe National Wildlife Refuge, New Jersey, USA. We determined the effect of site management history (unditched vs. ditched marsh) on adult and nest survival to aid in prioritizing future management or restoration actions. Seaside Sparrow apparent adult survival (61.6%, 95% CI: 52.5 - 70.0%) averaged >1.5 times greater than Saltmarsh Sparrow apparent adult survival (39.9%, 95% CI: 34.0 - 46.2%). Nest survival and predation and flooding rates did not differ between species, and predation was the primary cause of failure for both species. Apparent adult survival and nest survival did not differ between unditched and ditched marshes for either species, indicating that marsh ditching history may not affect breeding habitat quality for these species. With predation as the primary cause of nest failure for both species in New Jersey, we suggest that future research should focus on identification of predator communities in salt marshes and the potential for implementing predator-control programs to limit population declines.

The causes of dispersal and the cost of carry-over effects for an endangered bird in a dynamic wetland landscape.

The decision to disperse or remain philopatric between breeding seasons has important implications for both ecology and evolution, including the potential for carry-over effects, where an individual's previous history affects its current performance. Carry-over effects are increasingly documented although underlying mechanisms remain unclear. Here we test for potential carry-over effects and their mechanisms by uniting hypotheses for the causes and consequences of habitat selection and dispersal across space and time. We linked hypotheses regarding different types of factors and information (environmental conditions, personal and public information) predicted to impact reproductive success and dispersal for an endangered, wetland-dependent bird, the snail kite (Rostrhamus sociabilis plumbeus). To do so, we coupled structural equationmodelling with 20years of mark-recapture and nesting data across the breeding range of this species to isolate potential direct and indirect effects of these factors. We found that water depth at nest sites explained subsequent emigration rates via an indirect path through the use of personal, not public, information. Importantly, we found that these dispersers tended to initiate nests later the following breeding season. This pattern explained a phenological mismatch of nesting with hydrological conditions, whereby immigrants tended to nest later, late nesters tended to experience lower water depths, higher nest failure occurred at lower water depths and higher nest failure explained subsequent breeding dispersal. These results identified a novel potential mechanism for carry-over effects: a phenological mismatch with environmental conditions (water depth) that occurred potentially due to time costs of dispersal. Our results also highlighted a substantial benefit of philopatry - earlier initiation of reproduction - which allows philopatric individuals to better coincide with environmental conditions that are beneficial for successful reproduction. These results have implications for our mechanistic understanding and prediction of carryover effects, and emphasize that local conservation strategies, such as water management, can explain future demography at distant sites connected through dispersal.

Long‐term demography of the Northern Goshawk in a variable environment

Long‐term demography of the Northern Goshawk in a variable environment

Draft Genome Sequence of a Multidrug-Resistant Strain of Enterococcus faecalis, PM01, Isolated from the Nest of an American Bushtit, Psaltriparius minimus.

ABSTRACTPathogenic microorganisms associated with avian nests may detrimentally impact parental health and nest success for the nest primary users, potentially neighboring avian or terrestrial species, including humans. Here, we report the genome sequence of Enterococcus faecalis strain PM01, isolated from a failed nest of American bushtits, Psaltriparius minimus.

Depredation of Monteiro's Storm-Petrel (Hydrobates monteiroi) Chicks by Madeiran Wall Lizards(Lacerta dugesii)

Monteiro's Storm-petrel (Hydrobates monteiroi) is a small seabird endemic to the Azores archipelago, where it is known to breed only on two mammal-free islets. Total breeding numbers are between 250 and 300 pairs. During the 2015 breeding season on Praia Islet, six Madeiran wall lizards (Lacerta dugesii) were observed depredating a Monteiro's Storm-petrel chick about to fledge. In August 2015, a freshly killed chick without its head and four larger dead chicks were found. Eight other chicks had disappeared from their nests since our previous visit in early July. In 2016, there was further evidence of suspected lizard depredation. Three chicks were found predated and dragged out of their nests, and an additional 22 chicks disappeared from their nests before fledging. In 2016, Monteiro's Storm-petrel breeding success was only 26.8%, the lowest ever recorded. We suspect that some of the chick deaths and nest failures may be attributed to these introduced lizards. All chicks were found dragged out of their nests, a behavior that is not consistent with kills from aerial predators. Lizards were suspected because they are the only possible predator on land. Therefore, we recommend evaluating the impact of Madeiran wall lizards on the two Monteiro's Storm-petrel main colonies: Praia and Baixo Islets.

Poor reproductive success of Gray Vireos in a declining California population

Since the 1940s, populations of Gray Vireos (Vireo vicinior) in California have collapsed, presumably because of parasitism by Brown-headed Cowbirds (Molothrus ater). In 2012 and 2013, we studied the vireo's nesting ecology to assess factors affecting two of California's largest remaining populations in the chaparral of San Diego County. Nest success was extremely low, with a model-averaged probability of nest survival of only 0.08 (N = 95). More nest failures were due to predation (83%) than to cowbird parasitism (13%). Video-recording at 30 nests revealed that California Scrub-Jays (Aphelocoma californica) were the most common nest predator (67%). Of eight variables tested, height of shrubs surrounding the nest had the strongest negative influence on nest survival, but was more strongly correlated with cowbird parasitism than with jay predation. Despite frequent renesting, seasonal productivity was well below the level required to sustain a population, especially in northern San Diego County where we found no Gray Vireos at six of seven sites where they had been present from 1997 to 2001 and where cowbird parasitism was more frequent. The vireo's continuing range collapse contrasts with recent climate-change models predicting a range expansion, highlighting the importance of demographic studies. Low nest success is likely contributing to population declines in California, and the additive effect of cowbird parasitism suppresses productivity. Conservation of Gray Vireos in California will likely require development of alternative approaches to cowbird and scrub-jay control appropriate to sites widely scattered in rugged chaparral.

Population status, breeding success and ecology of the Henderson Petrel after a failed rat eradication on Henderson Island

ABSTRACTOne of the most important breeding colonies for gadfly petrels in the sub-tropics, Henderson Island in the South Pacific Ocean, was subjected to a rat eradication attempt in 2011, but the eradication failed. Here we examine whether the current population status of the endemic Henderson Petrel Pterodroma atrata is consistent with an ongoing population decline. We collected basic biological information on Henderson Petrels in 2015 to compare estimates of breeding population size and nest survival to data from 1991. We found that the extrapolated population size of 19 987 pairs was marginally higher than the comparable estimate of 18 668 in 1991. We also estimated the nest survival of 25 nests to be 28.5%, and most nest failures occurred within 7 days of hatching when chicks were killed by rats (n = 3) or a crab (n = 1). Breeding success was higher than in 1991, and possibly sufficient for a stable population. Although differences in survey effort render it difficult to directly compare estimates from 1991 and 2015, there is currently no evidence that the conservation status of the Henderson Petrel has deteriorated since it was listed as ‘Endangered’ by the IUCN.

A Rat-Resistant Artificial Nest Box for Cavity-Nesting Birds

The puaiohi or small Kauai thrush (Myadestes palmeri) is an endangered bird endemic to the island of Kauai, Hawaii. The sole population of about 500 birds is currently restricted to remote, higher elevation areas of the Alakai Plateau. Puaiohi nest primarily on steep streamside cliffs, and their distribution and abundance are limited by availability of suitable nesting sites. Black rats (Rattus rattus) cause nest failure and mortality of nesting female puaiohis, and ground-based rodent control has not been effective at reducing nest predation. In 2007, we investigated whether artifi cial nest structures might be a viable alternative to rodent control by testing nest-box designs to fi nd one that was resistant to rats. In laboratory trials, we evaluated 3 designs that were currently being deployed as artifi cial nest boxes for puaiohi and found that they were not rat resistant. From these results, we developed and tested an improved design. Captive rats were unable to enter a nest box made from a 36-cm length of 15-cm-diameter plastic pipe with an overhanging entrance cut at an angle of 49 o .

Effectiveness of direct payments to increase reproductive success of sandbar-nesting river birds in Cambodia

SummaryDirect payments to communities or individuals have gained traction as a tool for species conservation; however, few studies have evaluated their effectiveness. From 2010 to 2014, we monitored nests and implemented a direct payment nest protection programme for six sandbar-nesting bird species on the Mekong River, Cambodia, and tested if nest protection improved reproductive success. Nests were guarded by community members; additionally, exclosures were used to protect nests of River Tern Sterna aurantia, the species of highest conservation concern. We investigated factors affecting nest and chick survival, and probability of nest failure due to egg harvest or predation. Nesting later in the season generally resulted in lower nest and chick survival. Nest protection improved survival rates of River Tern nests and chicks, and Small Pratincole Glareola lactea nests. River Tern nest success was 60% for exclosed (and guarded) nests, 29% for guarded (but unexclosed) nests, and 5% for unprotected nests. River Tern fledging success was 82% for exclosed chicks, 40% for chicks that were guarded only, and 2% for unprotected chicks. Small Pratincole nest success was 21% for guarded and 6% for unguarded nests. Egg harvest by humans was lower among protected nests and declined during the study. Nest predation by animals increased during the study despite nest guarding; however, predator exclosures effectively protected nests and chicks. Additional predator control measures could further improve reproductive success of sandbar-nesting birds. Overall, nest protection involving direct payments was highly effective, but required diligent use of nest exclosures, frequent monitoring, and strong community relationships.

Status of the Nile crocodile population in Pongolapoort Dam after river impoundment

The major Nile crocodile Crocodylus niloticus populations in South Africa are threatened by pollution, habitat alteration/destruction, and poaching. This has highlighted the importance of other minor populations. The Phongola River Nile crocodile population was previously considered as unsubstantial. Consequently, we investigated the Nile crocodile population numbers and status and the effects of the impoundment of the Phongola River on this. In 2009–2010 we determined a minimum population number of 281 Nile crocodiles in Pongolapoort Dam using a combination of survey methods. The population structure was identified as having a minimum of 116 (41.3%) juveniles (<1.2 m total length), 31 (11.0%) subadults (1.2–2.5 m total length) and 134 (47.7%) adults (>2.5 m total length). At the commencement of the breeding season in August, crocodiles congregated at a major basking site where the main tributary entered the dam. Three major nesting areas were identified, two of which were located on the river inlet to the dam. We identified approximately 30 nesting females during the 2009/10 nesting season. Several nests were predated by the Nile monitor Varanus niloticus. There was a total recruitment failure of nests along the river inlet to the dam due to a flash flood of the Phongola River in January 2010. This preliminary study suggests that the Pongolapoort Dam Nile crocodile population has a relatively high potential reproductive output, although their annual successes may vary greatly because of loss of nesting sites as a result of water-level fluctuations and predation. It appears that the river impoundment has generally had a positive impact on this Nile crocodile population, although suitable nesting sites may become limited. Continued long-term monitoring of the Nile crocodile population in Pongolapoort Dam is required to determine if the impoundment continues to support a viable population.

Nest predation of woodland birds in south-east Australia: importance of unexpected predators

ABSTRACTFor most passerines, nest predation has a major impact on breeding success; however, information on the identity of nest predators is scant. In 2012, we investigated the identity of nest predators that each year depredate about 50% of the nests of 21 species in a south-east coastal bird community in New South Wales, Australia. The current study is a 2-year extension of this study and shows that at this study site (a) predation accounts for at least 90% of nest failures, (b) identified nest predators comprised two reptiles, nine birds and five mammals, (c) the suite of predators changes each season, (d) the two major predators were the Eastern Whipbird (Psophodes olivaceus) and the Fan-tailed Cuckoo (Cacomantis flabelliformis), (e) the impact of the Red Fox and Feral Cat was minimal, and (f) there was a variable and complex interaction between the parasitic cuckoos and their hosts. The data show definitively the overwhelming importance of nest predation on fledgling production, and bring to light new and important data on several aspects of the suite of nest predators.

Landscape Features Affecting Northern Bobwhite Predator-Specific Nest Failures in Southeastern USA

Nest predation is a critical component in avian productivity and typically is the leading cause of nest failure for most birds. Several landscape features are thought to drive the behavioral interaction between northern bobwhite (Colinus virginianus; e.g., nest placement) and their predators (e.g., search methods for food acquisition). In order to understand habitat characteristics influencing predation, we studied bobwhite nests using 24-hour near-infrared video cameras. We monitored 675 bobwhite nests with cameras on 3 properties in northern Florida and southern Georgia, USA, during 2000–2006. To test the association between nest failures and specific failure causes with landscape structure, we calculated a suite of landscape metrics and examined these at 3 spatial scales (3.1 ha, 19.6 ha, and 50.3 ha). We found increased probability of nest success with greater proportions of, and proximity to, fallow and annually disked fields at larger scales (50.3 ha), but we found no landscape metrics to be important predictors of bobwhite nest failures at small scales (<20 >ha). Fallow and disked fields may provide alternative prey items (e.g., rodents) important in buffering nest predation. Relative to meso-mammal predation, we observed increases in proportion of the landscape in field to be related to lower incidental nest failures at the smallest scale (3.1 ha). Nests closer to feed lines were more likely depredated by meso-mammals than ants at the 2 larger spatial scales. Interestingly, the fate of a nest was independent of the fate of neighboring nests, suggesting bobwhite nest predation may be primarily incidental.

Observations of nesting in the Papuan Flyrobin and the Olive Flyrobin, and post-fledging care in the Torrent Flycatcher, all endemic to New Guinea

We studied parental care in the Jacky Winter Microeca fascinans at Gluepot Reserve, South Australia, for one breeding season from 16 August to 9 November 2001, supplemented by observations on breeding and social behaviour in September 2012. We monitored ten nests in 2001, nine of which were attended by pairs and one by three adults, and watched three nests for a total of c. 117 hours. Female incubation constancy was 69%, duration of incubation sessions averaged 4.58 minutes and absences from the nest 2.07 minutes. Mean number of nest visits per hour by two pairs during the incubation period was 10.6 and for a group of three adults (two males, one female) was 15.8. Female care included brooding, feeding of nestlings, and nest-hygiene. Male care included delivering food to the sitting female, feeding the nestlings, nest-hygiene, nest-defence, and territoriality. Mean female brooding constancy was 55%. Mean number of feeding trips per hour by male and female combined for the entire nestling period was 14.6. Older young, 12, 13 and 14 days of age, received 21, 20, and 29 feeds/h respectively or one feed about every 2 minutes. Mean number of visits per hour by male and female combined to a nest with two young was 16.5 for Days 1–10 and 20.4 for Days 11–18 of the nestling period. High nest-predation is discussed in relation to nest placement and concealment, high nest visitation during incubation and nestling stages, anti-predator behaviour, nest-defence and types of predators, and re-nesting capacity, and compared with other Australasian robins and northern temperate and tropical songbirds. The small nest, small clutch-size, high nest failure, and anti-predator posture and mottled plumage of nestlings suggest that nest-predation is a strong selective pressure in the Jacky Winter. However, the moderately long nestling period, brood-size reduction, high rates of feeding young and nest visits by both male and female, and short and frequent incubation and brooding bouts on and off the nest relative to other robins are not consistent with nest-predation theory, and suggest behavioural responses to food availability and an ultimate response to food limitation. Incubation behaviour on and off the nest, parental care of young, nest visitation and other life-history traits that influence reproductive effort are discussed to elucidate the breeding strategy compared with other Australasian robins. The nesting season, nest materials and dimensions, nest-site, and incubation and anti-predator behaviour of the Papuan Flyrobin Devioeca papuana , and nest and egg of the Olive Flyrobin Kempiella flavovirescens , both species endemic to New Guinea, are described. An observation of cooperative post-fledging care of two juvenile Torrent Flycatchers Monachella muelleriana is presented. Incubation feeding occurred in the Papuan Flyrobin and incubation constancy was 54%. Papuan Flyrobin incubation behaviour, such as nest-attentiveness, frequency of nest visits and duration of on- and off-bouts, and nest failure are discussed and compared with those of the Jacky Winter Microeca fascinans , Lemon-bellied Flycatcher M. flavigaster and northern temperate passerines. Flyrobin nest failure and potential avian predators are discussed.

Hatching asynchrony in birds: Multiple nesting attempts and the nest failure hypothesis

ABSTRACT Hatching asynchrony in birds, which occurs when incubation begins before egg laying is complete, has been a topic of study for many decades. The “nest failure hypothesis” posits that the distribution of the risk of nest predation across the nesting cycle (from egg laying to the fledging of young) determines the optimal degree of hatching asynchrony. If such risk is higher earlier in the nesting cycle, then much asynchrony (e.g., incubation on the first egg laid) is generally favored. Alternatively, if the risk of nest predation is concentrated later in the cycle, then greater synchrony (a late start to incubation) is favored. Adult mortality during incubation favors greater hatching synchrony. Existing models suggest that optimal hatching asynchrony should depend on the ratio of daily mortality risks prehatching and posthatching, or early and late in the nesting cycle. We show that these classic theoretical expectations depend critically on the assumption of a single nesting attempt per breeding ...

Can island specialists succeed as urban pioneers? Pied imperial-pigeons provide a case study

Context Long-term viability of wildlife populations may be influenced by the adaptive or maladaptive nature of behavioural shifts. Yet, in the short term, implications of novel behaviour are often uncertain, as they were for a newly formed urban nesting colony of pied imperial-pigeons (PIPs) on the mainland coast of north-eastern Australia. It represented unprecedented behaviour, as most of PIPs, also known as Torresian imperial-pigeons, Ducula bicolor/spilorrhoa, breed colonially on remote small islands. Aims The present study would (1) determine whether aggregated mainland nesting continued, (2) evaluate reproductive success, (3) evaluate spatial distribution of nests and (4) explore possible association of reproductive success with predator presence and broad indicators of food availability. Methods With assistance from volunteers, we found mainland PIP nests and revisited them intermittently to monitor progress. We calculated quantitative estimates of nest survival by the Mayfield method and evaluated reproductive output in relation to environmental data from independent sources. Key results During the 2012, 2013 and 2014 breeding seasons, we recorded 436, 387 and 417 PIP nest events at the new mainland colony. Daily nest-survival rates declined progressively and estimated fledgling output decreased over successive seasons from 0.66 to 0.44 per nest event. The highest mainland output was below that estimated for an island PIP colony (0.78) on the basis of sparse prior data. Across potential foraging grounds, there was no negative change in land use and no widespread adverse weather to account for diminishing success. We identified important causes of nest failure among mainland nesting PIPs to be predation, predominantly by birds, and anthropogenic hazards, including tree pruning and collisions with vehicles and windows of buildings. Conclusions With ongoing exposure to these hazards, mainland nesting PIPs cannot be expected to increase productivity; hence, the new colony may be a short-term phenomenon. We infer that the historic success of PIP populations in Queensland stems from their selection of breeding sites on remote islands that are largely free of relevant predators and anthropogenic activity. Implications Future conservation of extant PIP abundance will depend crucially on protection of island breeding sites, because multiple hazards of mainland nesting make it an unfavourable alternative strategy.

Patch Size and Nest Density Influence Nest Survival

Nest predation is the primary cause of avian nest failure and therefore an important driver of avian population growth. Studies indicate that landscape context plays an important role in nest success, and although this is widely attributed to changes in nest predator communities, landscape context also influences nest density which affects predator search area and effort. Much debate remains as to whether specifically the size of a habitat patch or the density of nests has the greatest effect on nest predation rates. We explored the interactions between landscape context, predator efficiency, and nest survival. Northern bobwhite quail (Colinus virginianus) possess specific habitat requirements within a small home range and are a short-lived species that relies upon high reproductive performance, which make them the ideal system to test the extent to which landscape context affects nest predation rates. We investigated the extent to which the size of a grassland patch versus nest density affects nest survival by studying the predation rates of 617 artificial nests during two 23 day trials on 12 study sites in south central Nebraska. To examine the effects of patch size, we selected 6 study sites that were small patches of grassland (including pastures and Conservation Reserve Program fields) ranging in size from 40-60 ha and 6 study sites that were approximately 50 ha sections of larger contiguous grasslands. A high density of artificial nests were placed on half of the small and large patch study sites with the remaining sites having a low density of nests, for the second trial the nest density treatments were switched for each site.