Nest Success Rates Research Articles

Factors Affecting Nest Success of Tufted Ducks (Aythya fuligula) Nesting in Association with Black-Headed Gulls (Larus ridibundus) at Loch Leven, Scotland

Abstract. Nest success and nest-site characteristics of the Tufted Duck (Aythya fuligula) were studied during the 1996 breeding season at Loch Leven, Scotland. Approximately 463 ± 47 Tufted Duck pairs nested in association with 6,674 ± 805 Black-headed Gull pairs (Larus ridibundus) on St. Serf's Island. Tufted Ducks had an apparent nest success rate of 79.5% (Range: 65.8%–83.6%; n = 73). Multiple logistic regression was used to test the hypothesis that nest-site characteristics, such as distance to colony edge, overhead and vertical nest cover and distance to nearest Tufted Duck or Black-headed Gull nest, affect nest success. By using only the Tufted Duck nests with a known fate (n = 60), distance to the colony edge was identified as the primary predictor of nest success (P = 0.004), with successful nests (31.60 ± 1.71 m) located farther from the colony edge than those that failed (18.75 ± 2.61 m). Results support the central-periphery nest distribution model which suggests that nests located in the cente...

Habitat selection and nest success of the Upland Sandpiper (<em>Bartramia longicauda</em>) in Ivvavik National Park, Yukon, Canada

The Upland Sandpiper (Bartramia longicauda) is a grassland shorebird species associated primarily with prairie habitats in central North America. A disjunct and poorly studied population also occurs in Yukon, Canada, and Alaska, United States. We studied habitat selection of nesting Upland Sandpipers in Ivvavik National Park, Yukon, at the scales of microhabitat (1-m radius around nest) and putative home range (11.3-m radius plots at nests and within 50 m of nest). At the microhabitat scale, the Upland Sandpiper selected nest sites with lower visibility from above than that of their home range (median 91.5%, range 70–98% versus median 99.0%, range 85–100%) and less-variable composition of vegetation than at random sites within the home range. Vegetation adjacent to the nest in the eastern quadrat was significantly shorter (mean ± standard error: 10.6 ± 1.55 cm) than that in other directions around the nest (> 13 cm); nest sites and microsites within home ranges were more often hummocky than random sites in the park. At the mesohabitat scale, Upland Sandpipers selected sites within home ranges with fewer trees than random sites within the park (10.3 ± 3.0 trees per 11.3-m-radius plot around nest versus 32.9 ± 5.9 trees per 11.3-m-radius plot in the park) and greater herbaceous cover (70.7% ± 3.0% versus 56.2% ± 3.7%). Despite the disproportionate use of sites with fewer trees, more herbaceous cover, and lower vertical visibility, these factors did not relate to nest success in our sample. Of the 24 nests found in 2010 and 2011, 22 contained four eggs and 2 contained three eggs. Upland Sandpipers at this high latitude site had a nesting success rate of 0.85 ± 0.01 and 0.56 ± 0.01 in 2010 and 2011, respectively, for a 21-day incubation period. Further assessment of the selected characteristics of nesting sites will improve our ability to predict the effects of northward shrub and tree encroachment on this grassland species.

Linking conservation actions to demography: grass height explains variation in greater sage‐grouse nest survival

Conservation success often hinges on our ability to link demography with implementable management actions to influence population growth (λ). Nest success is demonstrated to be important to λ in greater sage‐grouse Centrocercus urophasianus, an imperiled species in the North American sagebrush‐steppe. Enhancing this vital rate through management represents an opportunity to increase bird numbers inside population strongholds. We identified management for grass height as an action that can improve nest success in an analysis of sage‐grouse nests (n = 529) from a long‐term study (2003–2007) in the Powder River Basin, southeast Montana and northeast Wyoming, USA. Average grass height by study area and year varied (11.4–29.2 cm) but its positive effects on nest survival were consistent among study years and study areas that differed in absolute rates of nest success. We tested the predictive ability of models by grouping output from log‐link analyses (2004–2006) into two bins with nest success probabilities < 0.45 and > 0.55, and validated the relationship with additional data from 2003 and 2007. Nests with probabilities > 0.55 were 1.64 (2004–2006) to 3.11 (2007) times more likely to hatch than those < 0.45, except in 2003 when an early wet spring resulted in universally high grass height at nest sites (29.2 cm) and high predicted nest success (64%). The high predictive power of grass height illustrates its utility as a management tool to increase nest success within priority landscapes. Relationships suggest that managing grass height during drought may benefit sage‐grouse populations.

Effect of Wind Turbine Proximity on Nesting Success in Shrub-nesting Birds

Wind energy development is rapidly expanding globally, as are concerns about the potential threats wind facilities pose to bird and bat populations. To date, many studies have explored the direct impacts of wind turbines on wildlife, such as wildlife-turbine collisions, but few have addressed indirect impacts, such as habitat degradation. These potentially subtle impacts can have far reaching effects on the abundance, distribution, survival, and breeding success of wildlife. We conducted a study to assess whether proximity of wind turbines to shrub-nesting birds influenced rates of nest failure associated mainly with depredation and brood parasitism by Brown-headed Cowbirds (Molothrus ater). During the primary nesting period of five passerine species, we monitored 253 active nests. We used a logistic-exposure method to model nest fate as a function of the important variables identified (including distance from turbine and brood parasitism). Our results indicate little relation between nest success and distance to turbine, with one exception, the Blue-gray Gnatcatcher (Polioptila caerule). For this passerine, we found nests closer to wind turbines had a lower probability of being brood parasitized and subsequently had higher nest success rates. We recommend future studies explore the potential implications of wind energy development on brood parasites, such as the Brown-headed Cowbird. As there is regulatory and social pressure to devise management strategies that reduce the impact of brood parasites on species of concern, any opportunities to decrease the risk of brood parasitism could be of benefit.

Nesting success and productivity of Tucuman Parrots (Amazona tucumana) in high-altitude forests of Argentina: do they differ from lowland Amazona parrots?

Most of our knowledge of reproduction of wild parrots in the Neotropics comes from studies of tropical lowland species, with few studies addressing species of high-altitude forests. We studied the reproductive biology of Tucuman Parrots (Amazona tucumana) in north-western Argentina between 2004 and 2009. We obtained data on reproductive output for 86 nests and on causes of mortality for 94 nests. Mean clutch-size per nesting attempt was 3.6 eggs ± 1.0 (s.d.). Hatching success (proportion of eggs laid that hatch) was 0.77 ± 0.17. Fledging success (proportion of nestlings that fledge) was 0.83 ± 0.13. The overall breeding success (mean number of fledglings per laying female per year) was 2.3 ± 0.8. Overall finite nesting success (daily survival rate to the power of the nesting length) was 0.53 ± 0.27, and chick finite nesting success rate was 0.74 ± 0.22. We did not find differences in reproductive rate between Tucuman Parrots and other species of Amazona parrot from lowland habitats. Productivity and nesting success of Tucuman Parrots had high values in some years and low values in others. This was probably related to fruiting events of Podocarpus parlatorei—a critical food item. The main causes of nesting failure were predation (16%) and abandonment (12%). Our results suggest that for several species of Amazona in lowland habitats, predation and poaching may be the main limiting factors whereas climatic factors and food availability may contribute most to nesting failure at higher altitudes.

Effects of measuring nestling condition on nest success in the dickcissel (Spiza americana)

ABSTRACTHandling songbird nestlings is often necessary to investigate a variety of basic and applied research questions, but this may also introduce observer effects that could compromise indices of reproductive success. To test for potential observer effects while measuring nestling condition in a study population of dickcissels (Spiza americana), we handled nestlings from 18 of 30 nests in Prairie, Mississippi, USA. We used generalized linear mixed models to compare nest success rate with nests that were monitored but where nestlings were not handled. Confidence intervals for nest success rates overlapped broadly for nests with handled (0.84, 95% CI = 0.57–0.95) and unhandled nestlings (0.77, 95% CI = 0.44–0.93), and a likelihood ratio test indicated the effect of treatment did not approximate the data better than a null model. We also did not find evidence of adults rejecting or abandoning handled and banded nestlings. This suggests that it is unlikely we incurred negative impacts on nest success when measuring nestling condition in our study. © 2014 The Wildlife Society.

Nest Site Location and Success Rates of an Urban Population of Woodpigeon Columba Palumbus in Ireland

:ABSTRACTRecent decades have seen an increase in the number of woodpigeon frequenting cities and urban areas. Relatively few studies have assessed the nest site location, predation and breeding success rate of urban woodpigeons, and no such study exists in Ireland. The current study found that nest site location had a significant impact on the nest predation rates of an urban population of woodpigeon. Urban woodpigeons had a selective preference for nesting in evergreen trees, despite the fact that these nests suffered a significantly higher rate of predation than nests located in deciduous trees. Furthermore, woodpigeons nesting higher above the ground (at a height greater than five metres) suffered significantly lower rates of predation than those nesting closer to the ground (below five metres).

First breeding records of Nonggang Babbler (Stachyris nonggangensis) in a limestone area in southern China

Abstract We present the first breeding records of Nonggang Babbler (Stachyris nonggangensis), a newly described bird species found in the limestone area of southwestern Guangxi, in southern China in 2008. The records presented here include information on behavior, nest, egg, incubation, and reproductive success rate. We discovered six nests (including three active nests) through systematic checking and radio tracking. Most Nonggang Babblers were found to begin foraging in pairs (male and female) from mid to late March. They build their nests in April. The nests were placed in cavities in a limestone cliff or on a massive rock located on the mountainside at altitudes ranging from 206–323 m. The nests were made of aerial roots, leaves, twigs, and soft grasses. Nonggang Babblers would lay 4–5 pure white eggs with an average fresh weight of 4.80 ± 0.11 g. Female Nonggang Babblers would spend 74.5 ± 5.0% of the day incubating their eggs, and the incubation period would last >18 days. We propose that Nonggang B...

Effects of environmental stressors on nest success of introduced birds

AbstractUnderstanding the influence of environmental stressors on daily nest survival of introduced birds is important because it can affect introduction success as well as the ability to evaluate introduction programs. For long‐lived birds with low annual production, adjustment to local breeding conditions can take many years. We examined nest success rates of 2 introduced bird species, whooping crane (Grus americana) and trumpeter swan (Cygnus buccinator), in Wisconsin. Both species are long‐lived with low annual reproductive rates. Trumpeter swans were established in our study area approximately 10 years before whooping cranes. We predicted that trumpeter swans would show less sensitivity to environmental stressors. We used daily nest survival rates (DNSRs) as our response variable to model several environmental parameters including weather, phenology, and ornithophilic black flies (Diptera: Simuliidae). Additionally, we examined the influence of captive history, age, release method, energetics, and nesting experience on whooping crane DNSRs. Daily nest survival of whooping cranes was the most sensitive to stressors. Trumpeter swan daily nest survival showed less sensitivity to the same stressors. Daily nest survival for both species peaked later in the nesting season, after 30 April and before 30 May. We also found that the daily nest survival rate (DNSR) for whooping cranes was potentially affected by captive exposure (measured by generations removed from the wild). Our results highlight the difficulties associated with conservation of long‐lived birds with low annual productivity as they adjust to local breeding conditions and that nest phenology at the source location can determine how these conditions are interfaced. We recommend that the juxtaposition of source and introduction location nest phenology be considered prior to introduction site selection. Additionally, strategically selecting offspring from captive pairs with nest phenology similar to that of sympatric species at the introduction location should be considered. Published 2013. This article is a U.S. Government work and is in the public domain in the USA.

Patterns of host use by a precocial obligate brood parasite, the Black-headed Duck: ecological and evolutionary considerations

The Black-headed Duck (Heteronetta atricapilla) is unique among obligate avian brood parasites because its highly precocial young leave the host nest shortly after hatching and impose no post-hatching costs on their hosts. Accordingly, we might expect host-parasite interactions in this parasite to differ strikingly from those of other brood parasites — they should be able to parasitize a broad diversity of hosts and be highly successful with these hosts. We conducted the second detailed study ever completed on patterns of host use in Black-headed Ducks. Based on four years of system- atic searches of multiple marshes in Argentina, we found no evidence that Black-headed Ducks ever had nests of their own, confirming the previous conclusion that Black-headed Ducks are, indeed, true obligate brood parasites. Contrary to expectation, however, we found that Heteronetta is ecologically dependent on a surprisingly small number of host species — two species of coots and a gull — all of which are widespread and locally abundant species. Other species are numerically less important as hosts either because they are relatively uncommon, or because they are avoided by the ducks. In the three main host species, hatching success of the duck eggs was also surprisingly low (≤ 28%), based on expectations for a precocial parasite, mainly due to host rejection or neglect. Mortality due to predation on host nests, in contrast, was low for all three primary host species. These observations corroborate Weller's observations from a single-year study. The combination of a dependence on few primary hosts and a relatively low hatching success are inconsistent with some previous hypotheses for the evolution of obligate brood parasitism in Heteronetta. Instead, our observations, and those of Weller, suggest that intense nest predation in Austral wetlands, coupled with an abundance of a few common host species that aggressively defend their nests and obtain high nest success rates, may have been an important factor in the evolution of obligate parasitism in this enigmatic duck.

Nesting biology and sex ratio in a neotropical spider wasp,Priochilus captivum(Hymenoptera: Pompilidae)

Examination of more than 700 cells of the mud-nesting spider wasp Priochilus captivum (Pompilidae) in Trinidad, West Indies showed a nesting success rate of about 85%, unusually high for a solitary wasp. Examination of prey remains from unsuccessful cells showed that almost all prey were jumping spiders (Salticidae). Adult females are larger than males, and the sex ratio at emergence is moderately male biased, as expected. Examination of randomly chosen pairs of offspring from the same nest indicated no skewed sex ratio.

Effects of Vegetation, Corridor Width and Regional Land Use on Early Successional Birds on Powerline Corridors

Powerline rights-of-way (ROWs) often provide habitat for early successional bird species that have suffered long-term population declines in eastern North America. To determine how the abundance of shrubland birds varies with habitat within ROW corridors and with land use patterns surrounding corridors, we ran Poisson regression models on data from 93 plots on ROWs and compared regression coefficients. We also determined nest success rates on a 1-km stretch of ROW. Seven species of shrubland birds were common in powerline corridors. However, the nest success rates for prairie warbler (Dendroica discolor) and field sparrow (Spizella pusilla) were <21%, which is too low to compensate for estimated annual mortality. Some shrubland bird species were more abundant on narrower ROWs or at sites with lower vegetation or particular types of vegetation, indicating that vegetation management could be refined to favor species of high conservation priority. Also, several species were more abundant in ROWs traversing unfragmented forest than those near residential areas or farmland, indicating that corridors in heavily forested regions may provide better habitat for these species. In the area where we monitored nests, brood parasitism by brown-headed cowbirds (Molothrus ater) occurred more frequently close to a residential area. Although ROWs support dense populations of shrubland birds, those in more heavily developed landscapes may constitute sink habitat. ROWs in extensive forests may contribute more to sustaining populations of early successional birds, and thus may be the best targets for habitat management.

Breeding biology of the Spot-billed Pelican (Pelecanus philippensis) in Karaivetti Bird Sanctuary, Tamil Nadu, India

The breeding biology of the Spot-billed Pelican (<i>Pelecanus philippensis</i>) was investigated from September 2007 to September 2010 in Karaivetti Lake, Tamil Nadu, India. The Spot-billed Pelican breeds between November and April at the Karaivetti Lake. It also breeds roughly during the same period at other breeding sites in Tamil Nadu, except for the Vedanthangal and Karikili bird sanctuaries, where pelicans arrives much earlier and their breeding activities start and end to some extent ahead of the other sites, i.e., from September to March. In essence, the breeding season starts after the onset of the northeast monsoon in Tamil Nadu. A few days after their arrival, pelicans perform courtship display, form pairs, start nest construction and lay eggs. Courtship display is not as attractive and impressive as in other waterbirds. The clutch size varies from two to three eggs and the incubation period from 25 to 36 days. The fledging period varies from a minimum of 90 to a maximum of 102 days. The nest success rate of the Spot-billed Pelican at Karaivetti was 90.28% during the study period.

Landscape patterns of avian habitat use and nest success are affected by chronic gas well compressor noise

Anthropogenic noise is becoming a dominant component of soundscapes across the world and these altered acoustic conditions may have severe consequences for natural communities. We modeled noise amplitudes from gas well compressors across a 16 km2 study area to estimate the influence of noise on avian habitat use and nest success. Using species with noise responses representative of other avian community members, across the study area we estimated gray flycatcher (Empidonax wrightii) and western scrub-jay (Aphelocoma californica) occupancy, and gray flycatcher nest success, which is highly dependent on predation by western scrub-jays. We also explore how alternative noise management and mitigation scenarios may reduce area impacted by noise. Compressor noise affected 84.5% of our study area and occupancy of each species was approximately 5% lower than would be expected without compressor noise. In contrast, flycatcher nest success was 7% higher, reflecting a decreased rate of predation in noisy areas. Not all alternative management and mitigation scenarios reduced the proportion of area affected by noise; however, use of sound barrier walls around compressors could reduce the area affected by noise by 70% and maintain occupancy and nest success rates at levels close to those expected in a landscape without compressor noise. These results suggest that noise from compressors could be effectively managed and, because habitat use and nest success are only two of many ecological processes that may change with noise exposure, minimizing the anthropogenic component of soundscapes should be a conservation priority.

Reproductive success of cavity-nesting birds in partially harvested woodlots

Cavity-nesting birds are dependent on large declining and dead trees that are frequently removed during partial harvesting. We compared breeding densities, nest survival, nest site characteristics, food abundance, and reproductive parameters of six species of cavity-nesting birds in partially harvested and reference woodlots in southwestern Ontario, Canada. Silvicultural practices significantly altered woodlot structure, with treatment-specific effects on bark arthropod biomass, fledging dates for the Red-bellied Woodpecker ( Melanerpes carolinus (Linnaeus, 1758)), and site suitability for the Yellow-bellied Sapsucker ( Sphyrapicus varius (Linnaeus, 1766)). Red-bellied Woodpecker, Downy Woodpecker ( Picoides pubescens (Linnaeus, 1766)), and Hairy Woodpecker ( Picoides villosus (Linnaeus, 1766)) experienced lower breeding densities in recently cut sites. Daily survival rates were generally greater for nests positioned higher up in large trees and for Northern Flicker ( Colaptes auratus (Linnaeus, 1758)) nests excavated in healthy and hard wood. Conversely, the Black-capped Chickadee ( Poecile atricapillus (Linnaeus, 1766)) had higher daily survival rates in low, small trees (&lt;10 cm diameter at breast height) and sites with lower arthropod abundance. We conclude that although partial harvesting has the potential to decrease cavity-nesting bird breeding densities, conscientious cavity tree retention during harvest may provide suitable nesting sites that maintain high rates of nest success, regardless of the silvicultural treatments that we examined. However, further research is required to monitor these trends beyond a single harvesting rotation.

Vertical nest stratification and breeding success in a six mixed-species heronry in Taeseong, Chungbuk, Korea

In 2001, we conducted a study to assess the effects of differential arrival times and nest-site selection on reproductive performance in a mixed-species heronry consisting of six species in Taeseong-ri, Chungbuk, Korea. We recorded the arrival dates, nest heights, clutch sizes, and brood sizes after 15–20 days of the age of the birds' chicks. The grey herons and cattle egrets arrived first and last, respectively, on the colony site. In the homogenous vegetation structure of the breeding site, the pitch pine trees (Pinus rigida) were mainly used for building nests on 48 of the 50 pine trees (96%). The breeding species vertically stratifies the nest sites according to their body size, except for the cattle egrets and black-crowned night herons that nested at sites higher than those predicted from their body size. The mean nest success rates of the six species under study were positively correlated with the mean nest heights. Our findings suggest that aggressive interspecific interactions among neighbors influence nest-site selection to enhance breeding success.

Are Moroccan fruit orchards suitable breeding habitats for Turtle Doves Streptopelia turtur?

Capsule Although subject to human disturbance Turtle Doves do nest successfully in these olive and orange orchards. Aim To investigate the breeding ecology of Turtle Doves in a man‐made agricultural habitat in central Morocco. Methods Turtle Dove nests were monitored in orange and olive orchards over three years (2006, 2007 and 2008). Nest abundance, nest location, egg‐laying chronology, clutch size, nest survival rates and breeding success were determined and compared between orchard types. Results The Moroccan population of Turtle Doves start breeding earlier than European populations. Clutch size, nest survival rates and breeding success were similar in orange and olive orchards. Nest location differed between orange and olive trees. Nest densities were 16 nests/ha in olive orchards and 45 nests/ha in orange orchards. Nest success rate averaged 48%. Daily nest survival rates did not vary according to orchard types, year and date. In the two orchards, no nest position variables were significant predictors of nesting success. Conclusion Although highly frequented by people, fruit orchards seem to be suitable breeding habitats for Turtle Doves in this region.

Breeding biology of the Grey-headed Bulbul Pycnonotus priocephalus (Aves: Pycnonotidae) in the Western Ghats, India

The breeding biology of the endemic Grey-headed Bulbul Pycnonotus priocephalus was studied from 2003 to 2005 in Silent Valley National Park, Western Ghats, India. Nests were located during three field seasons from the arrival (December) to the dispersal of the birds (June) and collected data on various breeding parameters, availability of fruits and weather conditions. All nests were found in mid-elevation evergreen forests ranging from 900 to 1,400 m elevation. Breeding occurred in the drier months (January-May), which coincides with high fruit availability. Nest building lasted 3-8 days. Majority of the nests (72%; n = 39) were built on two plant species (Ochlandra travancorica and saplings of Syzygium sp.) and the mean nest height was 1.52 plus or minus 0.80 m (n = 52). Nests were randomly oriented around the nesting plants with a mean vector of orientation equaling 160.450. The clutch size averaged 1.53 plus or minus 0.50 eggs (range = 1-2; n = 47). Incubation and nestling periods were 13 plus or minus 0.87 (n = 9) and 12 plus or minus 0.50 (n = 9) days, respectively. Overall nest success was 10.79%. Nest success rates varied among incubation and nestling periods. Grey-headed Bulbul exhibit life-history traits associated with low productivity such as short breeding season, low clutch size, fewer broods per year and high predation rates indicating that deterioration of breeding habitats might seriously hamper the long-term survival of the species.

Sources of variation in the nesting success of understory tropical birds

Survival of offspring is a key fitness component and, for birds, the threat of predation on nests is especially influential. Data on rates of nest success from tropical regions are comparatively few, conservation‐relevant, and essential for assessing the validity of models comparing the life histories and behavior or birds across latitudinal gradients. We monitored over 2 000 nests in the lowland forests of central Panama and, using the logistic exposure to model the fate of nests, explored the importance of variation in rate of nest success according to type of nest, height of nests, among years, in early versus late nests, and at different stages of the nest cycle. Analyses of over 1 400 nests for 18 species revealed considerable variation among species in the daily survival rate of nests (range among 18 species=0.91 to 0.98), but nest type and stage of the nesting cycle were generally influential on the probability of nest success. Cavity or enclosed nesters experienced greater nest success than open cup nesters and rates of nest loss were generally greatest in the nestling stage. We found limited evidence that height of nests affected probability of success, but no indication that timing of nesting effort was influential. Despite the occurrence of a severe ENSO event during our sampling, annual variation in nest success was not consistent among species. Interspecific variation in the rates and patterns of nest predation in our study, coupled with reports of high rates of nest loss at temperate latitudes, lead us to question long standing assumptions about latitudinal trends in rates of nest loss. We urge further work to understand the implications of nest predation on the evolutionary ecology of tropical birds.

Nesting Ecology of the Rusty Blackbird in Alaska and Canada

Abstract. We examined the nesting ecology of the Rusty Blackbird (Euphagus carolinus) from 162 nests monitored for nest survival in Alaska and 252 incidental records from Alaska and Canada to identify important habitats for nesting and to test whether low rates of nest success are contributing to populations declines in Alaska. In coastal Alaska and throughout Canada, nests were primarily in conifers (85% of 212 nests). All conifer nests in Alaska and 80% of those in Canada were placed in spruce (Picea spp.), primarily black spruce (P. mariana). In Alaska use of small spruces (<8 cm dbh) was selective and resulted in high reproductive success—nest survival increased with black spruce density, and success of nests in spruce (79%) was higher than that of nests in deciduous vegetation (52%). Survival of nests in taller spruce declined, possibly from predation by red squirrels (Tamiasciurus hudsonicus). Rusty Blackbirds nested near water in interior ( = 8 m) and south-central Alaska ( = 30 m), and small spruc...