A quantitative analysis of habitat preferences of Woodcock Scolopax rusticola in the breeding season

In Britain, prior to breeding, Woodcock Scolopax rusticola switch from feeding on pastures by night to feeding in woodland by day. Their major food is earthworms (Lumbricidae). In April and May 1985, vegetation structure and composition and soil parameters including earthworm numbers (30 habitat variables) were recorded for quadrats containing 50 feeding locations of six radio-tagged birds, seven nests and 50 random locations in Whitwell Wood, northeast Derbyshire.
Significantly different mean values between feeding and random sites were found for 11 habitat variables. Feeding sites were in younger stands, with a higher percentage ground cover of dog's mercury Mercurialisperennis and consistently high values for pH. Earthworm biomass was on average 82% greater than in random plots. Areas of beech Fagus sylvaticus were avoided. A discriminant function based on six habitat variables correctly classified 85-5% of the feeding and random sites; 70% of the feeding locations were correctly classified by a jack-knife procedure. The important factors determining where feeding occurs are probably safety from avian predators and high availability of earthworms.
Discriminant analysis of the habitats used for feeding by solitary birds, broods and for nesting produced significant functions which correctly classified 84% of sites. Nests were in areas with a high percentage cover of brambles Rubus spp. and more open ground vegetation. Broods and solitary birds used similar areas characterized by denser ground vegetation than nest sites.
The results of this study indicate that both habitat structure and food availability influence the distribution of Woodcock in the breeding season.     

No Habitat Selection during Spring Migration at a Meso-Scale Range across Mosaic Landscapes: A Case Study with the Woodcock (Scolopax rusticola)

Success of migration in birds in part depends on habitat selection. Overall, it is still poorly known whether there is habitat selection amongst landbird migrants moving across landscapes. Europe is chiefly covered by agro-forestry mosaic landscapes, so migratory species associated to either agricultural landscapes or woodland habitats should theoretically find suitable stopover sites along migration. During migration from wintering to breeding quarters, woodcocks (Scolopax rusticola) tagged with PTT satellite-tracking transmitters were used to test for the hypothesis that migrants associated to agro-forest habitats have no habitat selection during migration, at a meso-scale level. Using a GIS platform we extracted at a meso-scale range habitat cover at stopover localities. Results obtained from comparisons of soil covers between points randomly selected and true stopover localities sites revealed, as expected, the species may not select for particular habitats at a meso-scale range, because the habitat (or habitats) required by the species can be found virtually everywhere on their migration route. However, those birds stopping over in places richer in cropland or mosaic habitats including both cropland and forest and with proportionally less closed forest stayed for longer than in areas with lower surfaces of cropland and mosaic and more closed forest. This suggests that areas rich in cropland or mosaic habitat were optimal.     

Isolation of polymorphic microsatellite loci from Eurasian woodcock (Scolopax rusticola) and their cross‐utility in related species

We isolated one trinucleotide and seven tetranucleotide microsatellite loci for the Eurasian woodcock (Scolopax rusticola). We describe polymerase chain reaction conditions and primers for the successful amplification of these loci and report the results obtained from their use in 42 specimens from two populations in Europe. The number of alleles per locus ranged from three to 15, observed heterozygosity was comprised between 0.11 and 1.00 and expected heterozygosity ranged between 0.10 and 0.91. Cross‐specific amplification experiments highlighted the potential usefulness of these molecular markers for the study of three related scolopacid waders.     

Habitat selection in spatially heterogeneous environments: a test of foraging behaviour in the clonal submerged macrophyte Vallisneria spiralis

1. To test whether clonal macrophytes can select favourable habitats in heterogeneous environments, clonal fragments of the stoloniferous submerged macrophyte Vallisneria spiralis were subjected to conditions in which light intensity and substratum nutrients were patchily distributed. The allocation of biomass accumulation and ramet production of clones to the different patches was examined. 2. The proportion of both biomass and ramet number of clones allocated to rich patches was significantly higher than in poor patches. The greatest values of both clone and leaf biomass were produced in the heterogeneous light treatment, in which clones originally grew from light‐rich to light‐poor patches, while clones produced the most offspring ramets in the treatments with heterogeneous substratum nutrients. Similarly, root biomass had the highest values in nutrient‐rich patches when clones grew from nutrient‐rich to nutrient‐poor patches. 3. The quality of patches in which parent ramets established significantly influenced the foraging pattern. When previously established in rich patches, a higher proportion of biomass was allocated to rich patches, whereas a higher proportion of ramet number was allocated to rich patches when previously established in poor patches. 4. Results demonstrate that the clonal macrophyte V. spiralis can exhibit foraging in submerged heterogeneous environments: when established under resource‐rich conditions V. spiralis remained in favourable patches, whereas if established in adverse conditions it could escape by allocating more ramets to favourable patches.     

Habitat selection as a hierarchy: the spatial scales of winter foraging by muskoxen

We studied the winter resource selection of muskoxen Ovibos moschatus in the High Arctic using a nested hierarchy of spatial scales 1) population range, 2) travel routes, 3) feeding sites (l e clusters of feeding craters), 4) feeding craters, and 5) diet (I e plant species) We found that, generally, patterns of selection remained consistent across all levels At successively smaller scales, muskoxen selected for higher graminoid abundance and particularly for thinner, softer snow cover, although we did not reject the hypothesis of random travel route selection Muskoxen uncovered forages from beneath the snow cover, by cratering, near the flonstic and nival extremes of availability Selection was consistently biased toward use of water sedge, Carex aquatilis As scale changed, however, muskoxen showed reversals of preference for some other forage species Diet was dominated by C aquatilis and cotton sedge, Eriophorum angustifolium , species characteristic of lowland meadows During spring melt, muskoxen moved to snow-free uplands to feed Dietary quality, as revealed by fecal nitrogen, increased at this time The consistency of the results across scales implied that these local levels of habitat selection occurred within one scaling domain     

Habitat selection of breeding and migrating icterine warblers Hippolais icterina: a multivariate study

Site occupancy of migrating and breeding lcterine warblers was studied with respect to unoccupied randomly chosen sites in a willow and poplar mixed forest along the river Danube in Hungary Multivariate discriminant analysis revealed 4 different zones in the ordination diagram exclusive breeding zone, exclusive migrating zone overlapping zone, and an unused zone They were separated according to foliage cover and tree height Tree species composition mostly affects habitat use through physiognomy There was a partially overlapping, but clear difference in habitat selection between the migrating and the breeding birds     

Habitat requirements and foraging behaviour of the Corsican nuthatch Sitta whiteheadi

We examined the relationship between the Corsican nuthatch Sitta whiteheadi , a passerine endemic to the island of Corsica and Corsican pine Pinus nigra laricio forest, its virtually exclusive habitat, currently restricted to inland mountains. The Corsican nuthatch prefers older Corsican pine stands with tall, large trees, and avoids younger stands, both in the breeding and wintering seasons. This preference is explained by the greater availability of pine seeds from older trees. Territorial adults are almost completely sedentary, a trait that is influenced by seed hoarding behaviour. From late autumn to early spring (i.e., when cones are mature), and during sunny weather (i.e., when cones are open), nuthatches remove pine seeds from cones and cache them on branches and under the bark of trunks. The birds retrieve the cached seeds in cold and wet weather. The presence of old Corsican pine stands appears to be a key-factor in the survival of the Corsican nuthatch, whose habitat is currently threatened by logging and fires.     

Influence of breeding on foraging behaviour and diet of Crowned Cranes

Gichuki, N. 2000. Influence of breeding on foraging behaviour and diet of crowned cranes. Ostrich 71 (1 & 2): 74–79.

This study investigated the effects of breeding on the foraging behaviour and diet of Grey Crowned Cranes Balearica regulorum in the Kitale area, western Kenya. During the study period (July 1994 to June 1996), 86 pairs successfully bred in 290 ha of wetlands. Egg-laying extended from July to November, indicating that the timing of nesting was flexible. Breeding and non-breeding adult cranes as well as immature birds foraged in grasslands, crop stubble, sown fields and wetlands. These habitats were not used according to the available proportions. Breeding commitments restricted parental adults to habitats within their territories while non-parental adults and sub-adults exploited a wider range of habitats. Further, breeding adults and juveniles had smaller foraging range sizes than those of non- breeding adults and sub-adults. Reduced foraging ranges by breeding birds appear to be a trade-off between energy expenditure in self-maintenance and reproduction. The diet of breeding and non-breeding adults was generally similar consisting of graminoid seeds and arthropods. Breeding birds, however, increased consumption of protein rich animal food and non-seed plant material. Selectivity of food items was greatest among breeding adults. Overall, breeding commitments resulted in reduced foraging range and variety of food items available but the major components of the diet remained the same for all adults and immature birds.     

Application of a roding survey method to the sedentary Eurasian Woodcock <Emphasis Type=Italic>Scolopax rusticola</Emphasis> population in Pico Island,Azores

The Eurasian Woodcock Scolopax rusticola is a resident species in Azores, Madeira and Canaries (Macaronesian archipelagos) in contrast to its mainly migrant continental populations. The biology and ecology of these insular populations are still poorly known; however, woodcocks are hunted in Azores and Madeira. This work aims to continuing bridging the gap between scientific knowledge and game management of woodcocks in Azores. Working at Pico Island, the main objectives were: (a) to characterize the roding activity of these insular populations, (b) to select the best period of the breeding season to perform a roding survey and (c) to evaluate how sensitive is this method to variations in abundance because of hunting. From January to July 2002, the number of contacts with roding birds (males) was recorded, at dusk, at three observation points. Roding started in the beginning of February and lasted until late June/early July. The weekly variation in the number of contacts was similar in all points, strongly suggesting that the roding survey should be performed between the beginning of March and middle April. Two of the three observation points, located in an area where woodcock hunting is allowed in alternate years, were surveyed between March 1 and April 15, 2001–2005. The two points presented a similar annual variation pattern in the number of contacts, also suggesting stability in abundance. Sex ratio among birds bagged during three consecutive hunting seasons (October–November, 2002–2004) or among birds collected periodically during two winters (2000–2002) was equal to one, suggesting that annual fluctuations by the roding survey can be extended to the female fraction.     

Habitat selection and diet of Great Snipe Gallinago media during breeding

The Great Snipe Gallinago media is considered to be an endangered species. This paper examines its food and habitat use on a sub-alpine/low-alpine breeding area in central Norway. It was estimated that earthworms constitute more than 90% of Great Snipe food (by weight). Feeding birds selected the low herb willow scrub vegetation community and to a lesser degree eutrophic fen. Birds did not selectively feed on eutrophic dwarf birch/juniper heath despite it being the third most used vegetation community by virtue of its extent. Although soil penetrability, vegetation cover and earthworm density varied across vegetation communities, Great Snipe selected sites with similar habitat characteristics in different vegetation communities. Great Snipe seemed to select for an optimal combination of soil penetrability and earthworm density, and for medium scrub cover. Nests were found in a broad range of vegetation communities, but only low herb willow scrub was selectively used. However, an equal number of nests was found in eutrophic fen due to its larger extent. Dense vegetation cover around nests and short flushing distance of incubating females indicate low sensitivity to disturbance. We consider the Great Snipe to be a food and habitat specialist, requiring habitats rich in sub-surface invertebrates to breed. This may explain its scattered distribution in Scandinavia, and may render it vulnerable to habitat modification and loss.     

Habitat associations of Eurasian Skylarks Alauda arvensis breeding on Irish farmland and implications for agri-environment planning

Capsule Skylarks breeding in Ireland prefer extensive grassland habitats and almost completely avoid tillage habitats.

Aims To describe the distribution and habitat use of breeding Skylarks in Ireland, particularly in lowland agricultural habitats, and to use this information to inform conservation measures for this species.

Methods Countryside Bird Survey (CBS) and Farmland Bird Project (FBP) data were examined to determine large-scale (national) distribution and habitat selection, in addition to smaller-scale (farm- and field-level) habitat use. The CBS is a national breeding bird monitoring scheme involving 397 1-km squares. The FBP collected detailed bird and habitat data from 122 farms.

Results CBS and FBP data both showed significant regional differences in breeding Skylark densities, with the highest relative abundances in the northwest and west. Dry grassland/grass moor habitats supported the highest densities of breeding Skylarks in the CBS, which were significantly higher than in improved grassland or tillage. At the farm-level, Skylark numbers were positively related to wetland habitats but negatively associated with trees in field boundaries, dense ground vegetation and overall density of farm boundaries. At the field-scale, larger fields and unimproved grasslands were preferred.

Conclusion Agri-environment measures tailored to region-specific requirements and to the relatively local habitat preferences of target species are required if population declines of species of conservation concern, including Skylarks, are to be reversed.     

Habitat selection and foraging success by an endangered Mediterranean cyprinid: implications for habitat restoration

Hydrobiologia - Habitat loss and degradation are causing collapses in freshwater fish in the Mediterranean region, where habitat restoration actions are still hampered by poor understanding of fish...     

Habitat selection and foraging success of Hen Harriers Circus cyaneus in west Scotland

The foraging behaviour of Hen Harriers breeding in west Scotland was studied in a variety of afforested and moorland habitats. Time budget information from sample areas, stratified by habitat type and controlled for nest distance, was used to investigate habitat selection. Preferences were then related to measures of foraging performance in each habitat. Hen Harriers foraged preferentially over young first rotation coniferous forests, and selected heathland and grassland habitats ahead of closed canopy woodland. Harrier preference for the various habitats was positively correlated with the frequency with which they struck at, and captured, prey. Prey strike success was much lower than that reported for moorland managed for Red Grouse Lagopus lagopus scoticus. The results explain many of the reported changes in local Hen Harrier populations. The extent of young first rotation forestry is currently in decline. It is predicted that this will lead to a reduction in numbers of Hen Harriers breeding in west Scotland, and an increase in the proportion of the British harrier population occupying moorland managed for Red Grouse.     

Habitat use and foraging behaviour of urban merlins (Falco columbarius) in winter

Habitat use and foraging behaviour of resident merlins (Falco columbarius) wintering in Saskatoon, Canada, were studied over a five-year period. Birds were trapped through the winter and selected individuals fitted with radio transmitters to monitor continously their location, movements and activities from roost departure until re-entry. Merlins maintained individual home ranges in winter, with extensive overlap between neighbouring birds in some cases. Yearling home ranges were not significantly different in size from those of adults. The winter home ranges of adults were closely associated with their previous nest site. Both adults and yearlings made significantly greater use of Residential habitat in the city than expected based on the area available in their home ranges. However, while adults remained largely in the two oldest habitat types, yearlings were also found in more recently built areas of the city. Home ranges held within the city were sometimes combined with foraging areas in the adjacent countryside. The use of foraging areas in farmyards and cattle feedlots outside of the city was most notable in adults, although some yearlings apparently learned this strategy in their first year. Merlins also used Commercial-Industrial habitat for hunting at levels much higher than expected from its availability in their home ranges. Diets in summer and winter had a high degree of overlap; house sparrows (Passer domesticus) and bohemian waxwings (Bombycilla garrulus) made up a large proportion of the diet during both seasons. Hunting activity peaked at 09:00 and 16:00 h, reflecting the replenishment of energy stores lost over-night, and the storage of energy in preparation for the next over-night fast.     

From individual behaviour to population pattern: weather-dependent foraging and breeding performance in black kites

The links between weather and animal behaviour in population processes have received relatively little attention. I studied the effect of weather conditions on foraging and breeding performance of a medium-sized raptor, the black kite, Milvus migrans. The frequency of prey capture attempts and their likelihood of success increased with temperature and declined with rainfall. Kites used flight styles involving a higher energy expenditure in less favourable weather. Nestling provisioning rates declined during rain spells. More kites hunted during periods of favourable weather and after periods with a high frequency of successful prey capture attempts by conspecifics; this result suggested that individuals may fine-tune their foraging effort to the expected foraging reward. Such compensatory behavioural adjustments may increase species resilience to climate change. The behaviourally mediated effects of weather on prey availability translated into population effects. Yearly weather conditions during the last stage of the prelaying period affected population-level productivity, probably through an effect on female body condition mediated by male provisioning capability and hunting yield. The predicted effects of climate change on kites may already be occurring, with progressively earlier laying and northward range expansion. These results confirm the need to pay greater attention to behaviourally mediated effects of climate on populations, particularly when individuals make compensatory adjustments that may enhance resilience to climate change. Copyright 2003 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.      

Aploparaksis kornyushini n. sp. (Cestoda: Hymenolepididae), a parasite of the woodcock Scolopax rusticola (L.), and its life-cycle

Aploparaksis kornyushini n. sp. is described from a woodcock Scolopax rusticola L. from Lithuania, Russia (Tver' Region) and the Ukraine. Initially, one specimen of this tapeworm was described and figured by Kornyushin (1975) as A. scolopacis Yamaguti, 1935 together with another specimens belonging to the latter species. A. kornyushini n. sp. and A. scolopacis are morphologically very similar species. They can be distinguished by the slightly different length of the rostellar hooks and by the shape of the cirrus, which lacks basal bulbus in the new species. A. kornyushini can be readily distinguished from the remaining species of Aploparaksis Clerc, 1903 from woodcocks by the structure of its fully-developed embryophore, which has polar thickenings and two large or a few smaller lateral projection; this combination of characters is unknown for embryophores other Aploparaksis spp. (except for A. scolopacis). The life-cycle of A. kornyushini was studied under experimental conditions in Lithuania. The metacestodes were located under the chlorogogenous tissue of the intestine of Dendrobaena octaedra (Lumbricidae). The metacestode exhibits a pattern of postembryonal development typical for the cysticercoid modification termed an 'ovoid diplocyst'.     

Habitat selection rules in breeding mallards (Anas platyrhynchos): a test of two competing hypotheses

Ideal preemption and conspecific attraction are alternative hypotheses of the habitat selection rules used by individuals. According to the former an occupied site is assumed to be preempted and therefore not available for later arriving individuals, whereas according to the latter individuals are assumed to be attracted by conspecifics to occupied sites, rather than avoiding them. We studied these competing hypotheses in breeding mallards (Anas platyrhynchos) by a cross-over experiment in 2 years, introducing birds onto lakes before migratory wild mallards arrived. If mallards use the ideal preemptive rule, breeding density of wild mallards in experimental lakes should be lower and they should be occupied less frequently than control lakes, but if mallards use the conspecific attraction rule the reverse should be true. Our results allowed us to reject the ideal preemptive rule whereas the conspecific attraction rule was to some extent supported. We discuss these findings in relation to population limitation. The results suggest that the local breeding population studied is not limited by spacing behaviour related to habitat selection. Received: 14 July 1997 / Accepted: 17 November 1997     

Hummingbird foraging and the relation between bioenergetics and behaviour

Because of their small size and expensive mode of flight, hummingbirds display some of the highest known mass-specific rates of aerobic metabolism among vertebrates. High enzymatic flux capacities through pathways of carbohydrate and long-chain fatty acid oxidation indicate that either substrate can fuel flight. Although hummingbirds are known to rely on fat to fuel migratory flight, short foraging bouts are fueled by the oxidation of carbohydrate, not fat. This allows birds refueling at meadows during migration to deposit fat at higher rates and avoids the energetic inefficiency that results from synthesizing fat from dietary sugar, and then breaking down the fat to fuel foraging flight. On cold mornings in subalpine meadows, refueling hummingbirds achieve net energy gain despite the high energetic costs of thermoregulation and flight. In doing so, they sustain the highest known time-averaged metabolic rates among vertebrates. However, low sucrose concentrations, provided in volumes large enough to allow the maintenance of energy balance at low temperature, result in energy deficit and mass loss. The problem of disposing of dietary water at low ambient temperature when intake rates are elevated suggests that the kidneys may be involved in establishing the upper limit to intake rates and, therefore, maximum sustained metabolic rates. It is suggested that hummingbird behaviour and metabolism have coevolved to maximize net energy gain. Further, the energetics of hummingbird thermoregulation and flight may have influenced the evolution of sucrose content in floral nectar.