Nest-site Preferences Research Articles

Nest Site Preference and Nest Success in BlackcapsSylvia atricapillain Poland

Nest site preference and nest success in blackcaps Sylvia atricapilla in Poland.Predation is reported to be the main cause of nest failure in songbirds and selection of safer nest sites is thus an important determinant of breeding success. We studied the effect of nest site location: in bramble, elder or hornbeam, on breeding success as well as selection of different nest sites in the blackcap Sylvia atricapilla, a species whose nests are heavily preyed upon both by rodents and corvids. We found that breeding success differs between nest site types, with higher levels of predation of nests built in elder or hornbeam than of those in bramble. We also found that blackcaps select bramble when it is available within the nesting territory. Nests in bramble were better concealed than those in elder or hornbeam. Since nest height above the ground did not differ according to the plant species used, nest concealment was probably the main factor affecting blackcap nest survival.

Between a Rock and a Hard Place: Impact of Nest Selection Behavior on the Altitudinal Range of an Alpine Ant,Formica neorufibarbis

Formica neorufibarbis Emery is a dominant alpine ant in North America. Above timberline, colonies nest under rocks, placing brood against the rock surface to warm during the day. We tested the hypothesis that nest rock preference represents a mechanism of behavioral thermoregulation and used a demographic model to explore its impact on the species' altitudinal range. Under sunny conditions rocks provide warm microclimates. Across a 400-m altitudinal gradient from below timberline to high alpine tundra, nest rocks warmed on average 5°C above ambient at mid-day, but cooled to near ambient before dawn. Soil was warmer at mid-day under rocks occupied by ants than under randomly chosen unoccupied rocks in the same area. Occupied nest rocks were painted white or black to manipulate temperature and test its impact on colony occupancy. In addition, black-painted and white-painted rocks of similar size were placed in the field to test for a temperature effect on nest site colonization. Likelihood of nest persistence and colonization decreased under cooler, white-painted rocks and depended strongly on rock warming capacity. Experimental results showed that nest site colonization and occupancy are favored in microsites maintaining mid-day temperature ≥22°C. Across the altitudinal gradient, 66-90% of nest microsites occupied by F. neorufibarbis met this temperature threshold. Conversely, none of the exposed microsites and only 15% of those microsites under randomly selected rocks warmed to 22°C at the high altitude site (3,900 m). Results support the conclusion that nest site preference contributes to the broad altitudinal distribution of F. neorufibarbis.

Do parasitic common goldeneyeBucephala clangulafemales choose nests on the basis of host traits or nest site traits?

Conspecific brood parasitism (CBP) is an important alternative breeding strategy for gaining reproductive output in birds. While interactions between hosts and parasites and consequences of CBP to breeding success of both parties have been studied a lot, the roles of host characteristics and nest site characteristics in CBP have received less attention. We studied the relative importance of host‐related traits, such as female condition and breeding experience, and nest‐site‐related factors, such as overall nest site preference and occupation rate, in explaining the occurrence of CBP in a common goldeneyeBucephala clangulapopulation. We used spatially and temporally extensive data sets, analysed the data with generalized linear mixed models that allowed us to account for the non‐independency of individual nesting attempts across females and nesting sites, and used an information theoretic approach in model selection and inference. About half of the nests were parasitized annually during the seven year study period. The occurrence of CBP decreased with advancement of the breeding season but late nests were also frequently parasitized. We found that the occurrence of CBP was better explained by nest‐site characteristics than host traits, implying that parasitic females target a given nest based on factors related to the nest site itself rather than on the host. Our results suggest that more attention should be paid to factors associated with nest site attractiveness and quality when studying laying decisions of parasites and the occurrence of CBP in general.

A comparison of the autecology of two seed-taking ant genera, Rhytidoponera and Melophorus

Members of the genus Rhytidoponera and, to a lesser extent, certain Melophorus spp. are keystone mutualists for the dispersal of seeds in the southwest of Western Australia, with important ramifications for the ecology and speciation of plants in this biodiversity hotspot. For this reason, it is important to understand the autecology of the relevant ant species and the way in which they interact with plant seeds. This paper addresses key aspects of the ecology of three such ant species, Rhytidoponera violacea (Forel), R. inornata Crawley and Melophorus turneri perthensis Wheeler. Data are presented on their geographic distribution, seasonality of foraging, diurnal activity, response to fire, nest site preference, nest structure, colony size, feeding habits, foraging response to seed availability, and seedling emergence from nests. The role of all three species as seed dispersers is confirmed, and all three species have ecologies that are well-suited for dispersal and survival of native plant seeds. Preservation of this interaction is important for the conservation of plants, and it is fortuitous that all three species are able to survive disturbance and return to rehabilitated areas. However, the smaller R. inornata, and to a lesser extent, the larger R. violacea, are vulnerable to invasive ant [Pheidole megacephala (Fabricius)] incursions. M. turneri perthensis is able to coexist with the invasive ant unless this is at high densities, probably as a result of its ability to forage during high temperatures when the invasive species is inactive.

Species diversity and distribution patterns of the ants of Amazonian Ecuador.

Ants are among the most diverse, abundant and ecologically significant organisms on earth. Although their species richness appears to be greatest in the New World tropics, global patterns of ant diversity and distribution are not well understood. We comprehensively surveyed ant diversity in a lowland primary rainforest in Western Amazonia, Ecuador using canopy fogging, pitfall traps, baits, hand collecting, mini-Winkler devices and subterranean probes to sample ants. A total of 489 ant species comprising 64 genera in nine subfamilies were identified from samples collected in only 0.16 square kilometers. The most species-rich genera were Camponotus, Pheidole, Pseudomyrmex, Pachycondyla, Brachymyrmex, and Crematogaster. Camponotus and Pseudomyrmex were most diverse in the canopy, while Pheidole was most diverse on the ground. The three most abundant ground-dwelling ant genera were Pheidole, Solenopsis and Pyramica. Crematogaster carinata was the most abundant ant species in the canopy; Wasmannia auropunctata was most abundant on the ground, and the army ant Labidus coecus was the most abundant subterranean species. Ant species composition among strata was significantly different: 80% of species were found in only one stratum, 17% in two strata, and 3% in all three strata. Elevation and the number of logs and twigs available as nest sites were significant predictors of ground-dwelling ant species richness. Canopy species richness was not correlated with any ecological variable measured. Subterranean species richness was negatively correlated with depth in the soil. When ant species were categorized using a functional group matrix based on diet, nest-site preference and foraging ecology, the greatest diversity was found in Omnivorous Canopy Nesters. Our study indicates ant species richness is exceptionally high at Tiputini. We project 647–736 ant species in this global hotspot of biodiversity. Considering the relatively small area surveyed, this region of western Amazonia appears to support the most diverse ant fauna yet recorded.

Nest site ecology of the cross river gorilla at the Kagwene Gorilla Sanctuary, Cameroon, with special reference to anthropogenic influence

The Cross River gorilla is the most endangered of all Great Apes. It is currently found in 14 apparently geographically separate and increasingly isolated populations, which face severe threats from habitat loss and the bushmeat trade. Recent years have seen greater efforts to conserve the Cross River gorilla across the landscape, but details of the ecology of individual populations that might help in conservation initiatives are lacking. Here, we report on the production of the first habitat map for the recently created Kagwene Gorilla Sanctuary (KGS), Cameroon, and the results of an analysis of nest site preferences of the gorillas that live there. Qualitative vegetation assessments were made to assign various categories to the topstory and understory throughout the sanctuary, and nest sites constructed between January 2006 and March 2008 were re-visited and assessed for possible site preferences. The habitat map revealed significant anthropogenic impact, with only 57% of the KGS being relatively undisturbed primary forest. Analysis of nest sites showed that ground nests are constructed preferentially in the dry season, on precipitous slopes, in light gaps and clearings, with an understory of mixed herbs. Tree nests are predominantly built in the wet season, in primary forest with saplings as the preferred understory. Gorillas avoid nesting in grasslands and farms, which visibly fragment the remaining forest in the sanctuary. The results have implications for the conservation and management of the Cross River gorilla at KGS, and offer new insight into the nesting ecology of this subspecies.

The Effects of Gravel Bar Construction on Breeding Long-Billed Plovers

In Japan, the habitat range of Long-billed Plovers (Charadrius placidus), a typical river-nesting species, has contracted by 17% over the past 20 years. In the Tama River, Kanto region, the Tama River Research Group created a gravel bar in 2001 and 2002 by removing an invasive and non-native woody plant, Black Locust (Robinia pseudoacacia), to restore the biodiversity of the river ecosystem. The study investigated the effect of the gravel bar creation on Long-billed Plovers and their nest-site preference during the breeding seasons in 2001–2004 and 2006. After gravel bar creation, the mean number (±SE) of observed Long-billed Plovers increased from 0.4 (±0.19) to 11.0 (±1.54), which indicates that artificially constructed habitats have a potential to restore populations of Long-billed Plovers. The hatching rates in the study site varied greatly (19% to 100%) from year to year, and comparison with earlier studies was difficult due to incomplete information about the breeding conditions and differences in survey methods. Nesting probability was affected negatively by gravel size and positively by distances from forest edges, even after considering spatial auto-correlation caused as a result of having continuous sampling grids.

Nest-Site Selection and Nest Survival of Early Successional Birds in Central Pennsylvania

Abstract We studied nest-site selection and nest survival of early successional birds at the Barrens Grouse Habitat Management Area in central Pennsylvania in 2006 and 2007. We compared vegetation at nests to that at sites 30 m distant to examine microhabitat characteristics related to nest-site selection and which characteristics were associated with nest survival. Daily nest survival probability was 0.968 ± 0.006 (SE) for Chestnut-sided Warblers (Dendroica pensylvanica), 0.935 ± 0.014 for Field Sparrows (Spizella pusilla), 0.955 ± 0.011 for Indigo Buntings (Passerina cyanea), and 0.960 ± 0.005 for all species combined. Nest-site selection was best characterized by high woody stem density for Chestnut-sided Warblers, Indigo Buntings, and all species combined. Nest survival increased with woody stem density, indicating that nest-site preferences may be adaptive. Ground cover best predicted nest placement for Field Sparrows but no measured variable affected nest survival for this species. We suggest that s...

Age-specific nest-site preference and success in eiders

Variation in nest concealment is puzzling given the expected strong selection for safe nest sites. Selecting a concealed nest may decrease the risk of clutch predation but hinder parents from escaping predators, providing a possible solution to this paradox. Because the relative value of current versus future reproduction may vary with breeder age or state, nest concealment may also vary as a function of these attributes. We tested four predictions of the female and clutch safety trade-off hypothesis in eiders (Somateria mollissima): (1) nest concealment is negatively related to escape possibilities, (2) our capture rate of females is higher in covered nests, (3) egg predation is higher in open nests, and (4) overall nest success is unrelated to nest habitat. We also analysed nest microhabitat preferences and nest success relative to breeder age and body condition, controlling for nest spatial centrality. As expected, nest concealment and potential escape angle were negatively related, and capture by us, indicating female predation vulnerability, increased with nest cover. Clutch size was smaller in open nests, suggesting higher partial clutch predation, while it was larger among experienced and good-condition breeders. The probability of successful hatching was unrelated to nest habitat, positively associated with breeder experience, and negatively associated with hatching date. Experienced females selected more concealed and centrally located nests without sacrificing potential escape angles. The age-specific spatial distribution of nests on islands was unrelated to nest initiation dates, indicating no apparent competition. The age-specific preference of eiders for concealed nests may reflect declining reproductive value with age or confidence in surviving despite selecting a concealed nest. The apparently positive relationship between female age and survival and fecundity in eiders refutes the former alternative. Individual improvement in choosing safe nest sites, coupled with differential survival of individuals performing well, most likely explains age-specific nest-site preference and success.

Ross's Gulls (<i>Rhodostethia rosea</i>) Breeding in Greenland: A Review, with Special Emphasis on Records from 1979 to 2007

This review summarizes breeding records of Ross’s gull in Greenland with special emphasis on the period between 1979 and 2007. The review comprises both previously published records (including some published only in Danish) and unpublished reports and breeding records from 2004 and 2006. The majority of the Greenland breeding records fall into two geographically isolated areas that differ in habitat and climate: the Disko Bay area in West Greenland and the Northeast Water Polynya in Northeast Greenland. Despite the fact that antagonistic interactions with arctic terns are common, Ross’s gulls show a nest site preference for the edge of tern colonies, suggesting breeding association between these species. A general increase in breeding records in Greenland since 1978 is most likely the result of increased ornithological effort. Successful breeding has not yet been confirmed, and a Ross’s gull fledgling remains to be seen in Greenland. The Greenland breeding records suggest an opportunistic strategy in choice of breeding site among vagrant and possibly first-time breeders.

Nest-site Selection in a Postfire Landscape: Do Parents Make Tradeoffs between Microclimate and Predation Risk?

ABSTRACT. Maternal preference for nest sites is predicted to be an adaptive consequence of selective pressures acting on parents and young at the nest site. Nest predation risk has been linked to nest-site placement in birds, but microclimatic extremes can impose fitness costs on both adults and young, and these two factors may conflict. I used the temporal and spatial variation in microclimatic conditions and nest predation risk generated by variation in wildfire severity to examine the relationship between nest-site preference, nest microclimate, and fitness costs to parents and young in the Dark-eyed Junco (Junco hyemalis), a facultative cavity-nester. Adults preferred to select exposed nest sites oriented toward the north—sites that consistently had the most moderate thermal regimes. Nestlings reared in burrow-type nests gained mass more slowly and experienced retarded skeletal growth compared with exposed nests, but slower growth was not explained by suboptimal nest temperatures, nestling provisionin...

Wild Bee Abundance and Pollination Service in Cultivated Pumpkins: Farm Management, Nesting Behavior and Landscape Effects

Recent declines in managed and feral honey bee populations have greatly increased interest in the current and potential role of wild pollinators in agricultural pollination. Pumpkin (Cucurbita pepo L.) has great potential to be served by wild pollinators because of a reliable and widespread group of bee species that are commonly associated with their flowers, including bumble bees (Bombus spp.), and, in the Americas, two genera of specialist ground nesting bees (Peponapis and Xenoglossa). We examined the effects of several key farm management practices and landscape variables on bee abundance in pumpkin on 20 farms in Virginia and Maryland during summer 2006. We evaluated bee abundance with respect to tillage, irrigation practices, soil properties, natural habitat (forest and grassland), flowering crop, and disturbed areas. Additionally, we examined nest site preference (within or outside of crop areas) of Peponapis pruinosa (Say) at one farm and in a large screenhouse. We found P. pruinosa nesting preferentially within crop areas and near the vines and leaves of their host plant. Although these bees typically place some of their brood cells within tillage depth, we did not find a tillage effect on their abundance at flowers. We found a negative effect of soil clay content (R2 = 0.24, P = 0.03) and a positive effect of irrigation (F1, 15 = 12.2; P < 0.001) on P. pruinosa abundance. Using published data on pollinator visitation requirements, we found wild bee densities were sufficient to fully pollinate all pumpkin flowers on 13-17 of the 20 farms studied.

Experimental evidence for nest-site competition between invasive ring-necked parakeets ( Psittacula krameri) and native nuthatches ( Sitta europaea)

Ring-necked parakeets ( Psittacula krameri) originate from Africa and Asia, but have been widely introduced and are thought to compete for nest-sites with native hole-nesting birds, raising concerns for the loss of native avifauna. In this study, we adopt a replicated before–after-control experimental design to test for competition between parakeets and native cavity-nesters. In experimental plots in Brussels, Belgium we blocked parakeet nesting cavities and conducted surveys to evaluate availability and use of cavities by parakeets and native hole-nesters. Numbers of breeding pairs, as well as cavity quality index – based on cavity occupancy rates – were evaluated before and after blocking. After blocking, numbers of native nuthatches ( Sitta europaea) declined significantly, largely due to nest take-overs by parakeets. Nuthatches and parakeets strongly overlap in preferred nest-sites and this overlap explains the competition that leads to a reduction in nuthatch numbers when suitable cavities become scarce. Average quality of parakeet nests was lower after blocking, indicating that parakeets will utilize alternative cavities when preferred sites are not available, bringing them into greater conflict with other cavity nesters. Although some nuthatches remain in areas dominated by ring-necked parakeets, our results raise conservation concerns for the vulnerability of native cavity-nesting birds to the expansion of invasive parakeet populations.

Assessing the ecological application of lasergrammetric techniques to measure fine-scale vegetation structure

In the study of habitat use by animals, it is important to sample vegetation structure or the degree of cover at different heights or in vegetation strata. Commonly-used techniques to estimate vegetation cover (e.g. point height intercept) are time-consuming and can be especially subjective in tall forest environments. We investigated the application of a Terrestrial Laser Scanner (TLS) to quantify forest structure, in terms of evenness and functional diversity. We also explored the suitability of the developed lasergrammetric technique (LGT) in the monitoring of nest site preferences of translocated populations of New Zealand endemic birds, the South Island saddleback ( Philesturnus carunculatus) and the New Zealand robin ( Petroica australis). At an acquisition rate of up to 6000 points per second and with an estimated error of less than 2 cm, the LGT technique utilises terrestrial scanners that allow collection and processing of field data rapidly and precisely. Further, LGT is able to account for small structural elements such as minor branches, leaves and vine stems. The derived measures (mean height of canopy (MCH), indices of structural evenness ( E var) and functional diversity ( FD var)) can quantified vertical variations in vegetation density but appeared highly dependent on the vertical scale of measurement. When applied to an ecological case study, results suggested that the LGT method provides complementary quantitative estimates to summary methods when assessing vegetation structure for micro-scale studies. However, further validations of the LGT accuracy are needed more specifically in relation to density of obstructing vegetation and when used in the measuring of small vegetative objects and total biomass estimates. The development of new software packages that easily convert large amounts of three-dimensional data collected using laser scanners, into a form ready for biostatistical analysis, also is strongly encouraged.

Selection and sharing of sheltered nest sites by ants (Hymenoptera: Formicidae) in grasslands of the Australian Capital Territory

Abstract In this study, it was investigated whether ants nesting under artificial rocks in a mesic south‐eastern Australian grassland showed preference for nest sites with different temperature regimes. The study also allowed evaluation of competition between species for nest sites and observations of seasonality in brood and alate production in the nests of four common ant groups. On every sampling occasion more than 90% of nests were eitherIridomyrmexspp.,Rhytidoponera ‘metallica’,Paratrechinasp. orPheidolespp. Soil underneath thinner artificial rocks had higher average temperatures and warmed up earlier in the day andIridomyrmexspp. andR. ‘metallica’showed preference for establishing nests under these. While all ant nests had summer peaks in brood production,Iridomyrmexspp. andR. ‘metallica’had brood observed throughout the year. Winged reproductives were commonly encountered inIridomyrmexspp.,R. ‘metallica’andParatrechinasp. nests, but only occasionallyPheidolespp. nests. Alates were present in the nests from February but released by all taxa after spring rains and were scarcely recorded in November, December and January when brood production was observed in most nests. Nest sites that offer protection from predators are an obvious advantage, but improved reproductive success can be gained in cool regions such as the mesic grasslands of the Australian Capital Territory by choosing nest sites with an optimal thermal regime.

Predominant Use of Windthrows by Nesting Eastern Woodrats (Neotoma Floridana) in the South Carolina Coastal Plain

ABSTRACT We conducted a study of nest site selection by the eastern woodrat (Neotoma floridana) in the South Carolina coastal plain. We identified 40 active nests in three macrohabitats: a bottomland hardwood–upland pine ecotone, a southern mixed hardwood forest and a disturbed maritime forest. We further conducted an analysis of 21 microhabitat variables at 27 active nests, identified through live-trapping and release. Previous studies suggest that stick houses are preferred nest sites throughout N. floridana's range, and that dwarf palmetto (Sabal minor) may be an important indicator of woodrat habitat in North Carolina. Eastern woodrats inhabited windthrown rootmasses in 77.5% of nests at our study sites. S. minor and stick houses were completely absent from two of the three habitats. Multivariate analysis revealed that nest sites differed from paired non-nest sites by containing higher coarse woody debris and rootmass volume, and lower basal area. We recommend that N. floridana population surveys rout...

Artificial nest site preferences of Black-capped Chickadees

ABSTRACT To facilitate study of the breeding biology of parids, Grubb and Bronson (1995; Condor 97: 1067–1070) designed artificial “snags” made from polyvinyl chloride (PVC) tubes. Because the cost of artificial snags is greater than that of traditional wooden boxes, we examined alternatives to PVC snags for attracting chickadees to artificial nesting sites. From 2005 to 2007, we compared the use of PVC snags and wooden nest boxes by Black-capped Chickadees (Poecile atricapillus) in Sapsucker Woods Sanctuary in Ithaca, New York. We also quantified the use of cavities with and without wood shavings. The probability of chickadee excavation was greater (60–70% per yr) in filled snags (with wood shavings) than in filled boxes (40–50%; logistic mixed model, P= 0.01), and chickadees initiated more nests in filled snags (25–30%) than filled boxes (15%; P= 0.03). Chickadees also initiated significantly more nests (P= 0.03) in filled than unfilled boxes. Although wooden boxes filled with wood shavings were used more often by Black-capped Chickadees than unfilled wooden boxes, artificial snags filled with wood shavings were used most, were no more likely than boxes to be usurped by House Wrens (Troglodytes aedon), and were less likely than boxes to be occupied by mice. Thus, artificial snags may be the better option for investigators studying the breeding biology of chickadees. Para facilitar estudios sobre la biología reproductiva de los paridos, Grubb and Bronson (1995; Condor 97: 1067–1070) diseñaron “tocones” artificiales hechos de tubos de policloruro de vinilo (PVC). Debido a que el costo de los tocones artificiales es mayor que el de las cajas de madera tradicionales, examinamos las alternativas a los tocones de PVC para atraer a Poecile atricapillus a lugares artificiales de anidación. Entre el 2005 y el 2007, comparamos el uso de tocones de PVC y cajas de madera por P. atricapillus en el santuario de Sapsucker Woods en Ithaca, Nueva York. También cuantificamos el uso de cavidades con y sin aserrín de madera. La probabilidad de excavación por P. atricapillus fue mayor (60–70% por año) en tocones con aserrín que en cajas con aserrín (40–50%; modelo logístico mixto, P= 0.01), y los individuos comenzaron mas nidos en tocones con aserrín (25–30%) que en cajas con aserrín (15%; P= 0.03). P. atricapillus comenzó significativamente mas nidos (P= 0.03) en cajas con aserrín que en cajas sin aserrín. Aunque las cajas de madera con aserrín en su interior fueron usadas mas frecuentemente por P. atricapillus que cajas de madera vacías, los tocones artificiales con aserrín en su interior fueron mayormente usadas y no tuvieron una mayor probabilidad de ser usurpadas por Troglodytes aedon y también tuvieron una probabilidad mas baja de ser ocupadas por ratones que las cajas. Así, los tocones artificiales pueden ser una mejor opción para investigadores quienes estudian la biología reproductiva de P. atricapillus.

RESOURCE SELECTION PLASTICITY AND COMMUNITY RESPONSES TO EXPERIMENTAL REDUCTION OF A CRITICAL RESOURCE

Resource selection plasticity and behavioral dominance may influence the ability of a species to respond to changes in resource availability, particularly if dominant species have highly specialized resource requirements. We examined the response of several dominant and subordinate cavity-nesting species to a reduction in the availability of an essential resource (nesting cavities) using the novel experimental approach of blocking the entrances to high-quality cavities. We monitored nest abundance on seven treatment and 13 control sites (aspen groves in a grassland matrix) in British Columbia, Canada, for two years pretreatment (2000-2001), two years during treatment (2002-2003), and two years posttreatment (cavities reopened; 2004-2005). At the community level, nest abundance declined by 50% on treatment sites following cavity blocking and returned to pretreatment levels following cavity reopening. Nest abundance of European Starlings (Sturnus vulgaris), a dominant secondary cavity-nester (SCN), declined by 89% and failed to recover posttreatment. Conversely, nest abundance of Mountain Bluebirds (Sialia currucoides; a subordinate SCN) increased following cavity blocking and remained high following reopening. Tree Swallows (Tachycineta bicolor) were unaffected by cavity blocking. We suggest that starlings, while being the dominant SCN, may be limited by availability of suitable nest sites, whereas bluebirds may be limited by starling abundance. We propose that plasticity in nest site preferences of subordinate cavity-nesters may enable them to contend with natural variation in availability of critical resources, such as nest cavities and food, in addition to coping with interspecific competition. This is the first community-level, multiyear study involving manipulation of nest site availability via experimental cavity blocking.

Comparison of the Prelaying Behavior of Nest Layers and Litter Layers

The Swiss Animal Welfare Act decrees that the housing conditions of farm animals must guarantee animal welfare. In the process of developing a method to test nest boxes for their suitability for laying hens, we conducted an investigation using preference testing. It was aimed at verifying the occurrence of different types of layers within the same laying strain and to investigate the choice of a nest site. At the onset of lay, 24 individually housed hens were given the choice of 2 nest sites: a nest box or a litter tray. The chosen nest site and the behavior of the hen, 1 h prior to oviposition, were recorded at 3 stages during the period in which the first 20 eggs were laid. The majority (17) of the hens laid consistently in the nest box, and 7 hens laid consistently in the litter tray. Litter layers spent more time exploring during the hour prior to oviposition than did nest layers, and their final nest visit (when an egg was laid) was shorter. There was no significant difference in the number of entries into the chosen nest site between layers of the 2 types. As expected, the level of restlessness of hens decreased with laying experience. In the hour prior to oviposition, the frequency of foraging and resting increased, whereas the frequency of exploring and nest seeking decreased, and the number of nest-site visits declined. We conclude that there may be at least 2 different types of laying hens that show different nest-site preferences, with concomitantly different prelaying behavior.

Against Oversimplifying the Issues on Relocating Turtle Eggs

Translocating sea turtle eggs at risk from high tides to safer places is one of the most widely undertaken conservation measures on behalf of these species. Recent research work has shown that individual female turtles differ in their nest-site preferences. If more of the nests saved by translocation come from turtles with tendencies to lay near the water, might this perhaps interfere with natural selection? This possibility adds to the controversy already surrounding relocation of turtle nests.