Habitat selection, diet, arthropod availability and growth of a moorland wader: the ecology of European Golden Plover Pluvialis apricaria chicks

Habitat use, diet and food supply of European Golden Plover Pluvialis apricaria chicks were studied on blanket bog in the South Pennines, UK. The home ranges occupied by chicks until fledging averaged 40 ha; they contained relatively more cotton grass and bare peat than was available generally, but less heather and grassland. Use of Bilberry Vaccinium myrtillus and Crowberry Empetrum nigrum increased with age, whereas that of cotton grass Eriophorum spp. declined. Dietary composition, as assessed by faecal analysis, was similar to that obtained from the crops of dead birds. The diet of younger chicks, assessed by dry weight of prey, consisted of about 30% each of adult and larval tipulids, whereas for chicks older than 16 days, about 70% was tipulid larvae. Beetles, spiders and caterpillars each comprised 5–20% of the diet, depending on age. Older chicks took larger prey. The exploitation of larval tipulids was correlated positively with the chicks' use of cotton grass and bare peat areas, whereas caterpillars, beetles and spiders were more often taken from dwarf shrubs, reflecting variation in prey abundance. Bare peat was an important foraging habitat, whose exploitation was associated positively with the growth rate of young chicks, and with mean prey size. Both weight gain and survival of young chicks were positively correlated with the abundance of tipulid adults, confirming the hypothesis that the flush of tipulid hatching is an important determinant of breeding success. Golden Plover chicks are capable of considerable movements to track variation in prey availability. This behaviour is likely to be an important survival strategy facilitating the utilization of a mosaic of cotton grass and dwarf shrub habitats. Appropriate rotational strip-burning or grazing management could be used to create and maintain such habitats.     

The effect of habitat quality on foraging patterns, provisioning rate and nestling growth in Corsican Blue Tits Parus caeruleus

Many bird species face seasonal and spatial variation in the availability of the specific food required to rear chicks. Caterpillar availability is often identified as the most important factor determining chick quality and breeding success in forest birds, such as tits Parus spp. It is assumed that parents play an important role in mediating the effect of environment on chick development. A reduction in prey availability should therefore result in increased foraging effort to maintain the amount of food required for optimal chick development. To investigate the capacity of adults to compensate for a reduction in food supply, we compared the foraging behaviour of Blue Tits Parus caeruleus breeding in rich and poor habitats in Corsica. We monitored the foraging effort of adults using radiotelemetry. We also identified and quantified prey items provided to nestlings by using a video camera mounted on the nest. We found that the mean travelling distance of adults was twice as great in the poor habitat as it was in the rich. Despite the marked difference in foraging distance, the proportion of optimal prey (caterpillars) in the diet of the chicks and the total biomass per hour per chick did not differ between the two habitats. We argue that relationships between habitat richness, offspring quality and breeding success cannot be understood adequately without quantifying parental effort.     

Arrival and habitat use by Lapwings Vanellus vanellus in the early breeding season

The arrival on the breeding grounds and habitat use in relation to agricultural land use by Lapwings Vanellus vanellus was compared in rough grazing and arable study areas in the Midland Valley of Scotland. First arrivals took place in early February. Males preceded females and territory occupation by the males began soon after first arrival. During the pre-breeding period birds remained in flocks and day time habitat use and activity was strongly influenced by the lunar cycle. Birds fed mainly in those habitats in which prey (leatherjackets and earthworms) were most plentiful, and in which their feeding success was high. The choice of nesting habitat was not influenced by food availability in the immediate vicinity of the nest site but by the crypticity of the clutch and incubating adults. On rough grazing birds preferred unimproved land while on arable land spring cereal was the preferred habitat. The choice of actual nesting field on the arable land was influenced by the risk of predation and the proximity of suitable feeding fields for the adults and chicks.     

The impact of vegetation characteristics and prey availability on breeding habitat use and diet of Little Owls Athene noctua in Central European farmland

Capsule Foraging habitats are determined by vegetation characteristics rather than the availability of insect prey.

Aims To determine the diet composition of Little Owls in relation to the availability of insects at foraging sites, and to elucidate the main factors determining the owls’ habitat choice.

Methods The feeding ecology of Little Owls was studied during the 2002 breeding season in the agricultural landscape of western Bohemia (Czech Republic), where its population is in decline. Diet composition was determined by pellet analysis. Insect availability was studied using pitfall traps in the two most important Little Owl foraging habitats. For both habitats, we assessed the main vegetative characteristics (average and maximum vegetation height, vegetation density).

Results Based on number, insects were the most dominant prey, followed by small mammals; based on weight, insects comprised only a minor part of the diet. Among insect prey, Carabidae beetles were the most abundant. The proportion of insect numbers was strongly positively correlated with advancing day of the season and negatively correlated with the proportion of vertebrates. Although the highest densities of Carabidae were found in cornfields Little Owls significantly preferred grassland habitats, probably because of the lower vegetation cover.

Conclusions The availability of short sward vegetation in grassland habitats during the breeding season may play a key role in the conservation of Little Owls in central European farmland.     

Changes in the Montagu’s Harrier Circus pygargus diet in Eastern Poland across decades promote insects and reptilians,but not birds and rodents

We investigated temporal changes in diet composition of the Montagu''s Harrier Circus pygargus breeding in natural habitat (calcareous peat bog) in SE Poland. We characterized diet composition in a three‐year period (2007–2009), based on pellet analyses. We investigated whether diet composition was affected by years or stage of breeding. We compared diet of the studied population between 2000s and 1990s and with other populations. We found that the food of the studied population was dominated by insects and mammals (by number) and mammals and birds (by biomass). Biomass and abundance of main prey items differed between studied years because of different air temperatures. We found some interannual differences in contribution of some prey items including higher number of thermophilic prey (insects and amphibians) in warmer years. Comparison of pellet composition in the 1990s and 2000s revealed significant increase in the abundance of thermophilic prey (insects and reptiles) and decrease of mammals including Microtus voles and birds. Those changes may be linked to habitat changes in areas neighboring peat bogs and climate change‐induced changes in prey communities. The studied population was able to respond to changes in foraging habitats and prey composition by opportunistic foraging on easily available prey. The diet of the studied population is the most similar to the geographically closest populations foraging in similar habitats and characterized by high contribution of insects.     

Habitat selection,diet and food availability of European Golden Plover Pluvialis apricaria chicks in Swedish Lapland

Fennoscandian alpine tundra habitats support large numbers of breeding waders, but relatively little is known about their breeding ecology despite the fact that this habitat is threatened by climate change. We studied habitat selection, diet and prey availability of European (Eurasian) Golden Plover Pluvialis apricaria chicks at the Vindelfjällen Nature Reserve, Ammarnäs, Sweden. Information from 22 chicks tracked using radio‐transmitters was analysed. By analysing 149 faecal samples, four main prey taxa were identified, Coleoptera (40%), Bibionidae (31%), Hymenoptera (13%) and Tipulidae (10%). We found that chicks switched from feeding on Tipulidae to feeding on Bibionidae as they grew, and that this switch coincided with a shift from the use of the habitat where Tipulidae were abundant (alpine meadow/heathland) to the use of the habitat were Bibionidae were abundant (Willow shrub). Although chicks track food availability to some extent, the link between prey availability and habitat use was not perfect, indicating that additional factors other than food abundance, such as shelter from predators, determine habitat selection. Bibionidae are an important prey for Golden Plover chicks as it is the only prey group that has a late summer flush in abundance, in contrast to the general decline of total arthropod biomass during the chick‐rearing period. However, Bibionidae imagoes only occurred in 2011 and were virtually absent in 2013, which relates to the species’ ecology with 2‐ to 5‐year cycles in mass occurrence. Extreme annual variation in an essential food source such as Bibionidae imagoes might have an important effect on the condition and survival of Golden Plover chicks, an important subject for future studies. The foraging conditions for Golden Plover chicks in Fennoscandia appear to be different to those in the UK, where the chicks rely mainly on a Tipulidae flush only.     

Foods of the Dartford warbler Sylvia undata on southern English heathland (Aves: Sylviidae)

This paper describes the invertebrates of Callunetum and gorse on lowland heaths in Dorset and relates how these were exploited by the Dartford warbler Sylvia undata , a scarce bird of interest to nature conservation and one of the small number of wholly insectivorous resident passerines in Britain. Gorse had a denser invertebrate fauna than Callunetum and was used for feeding at a frequency out of proportion to its abundance. Diets of adult birds closely reflected the taxonomic composition of the gorse and Callunetum faunas exploited in the observed proportions, though some noxious taxa were avoided and below a certain limit, creatures of above average size were selected. Major foods were beetles, spiders, lepidopteran larvae and bugs. Nestling birds received a diet differing in taxonomic composition and size from that of the adults, and variations between habitats were found which accorded with observations on the habitat preferences of the Dartford warbler. An experimental investigation showed the importance of gorse as a source of food for young and the adults flew considerable distances ignoring extensive deep stands of heather nearer to the nest. The possible influence of competing insectivorous vertebrates on Dartford warblers is discussed. Various mammals and reptiles appeared to be the major vertebrate predators in Callunetum, but little competition was anticipated in gorse. Scarcity of gorse on the heaths and low densities of invertebrates in heather explained the low densities at which Dartford warblers occur.     

Status of breeding Dotterel Charadrius morinellus in Britain in 1999

Capsule A minimum of 220 male Dotterel nested in Britain in 1999, which after correction for missed birds led to an estimated 630 breeding males.

Aims To provide a reliable population estimate of Dotterel against which past and future estimates could be compared.

Methods Over half of the potential breeding habitat in Britain, selected randomly and to cover protected sites and former breeding sites for Dotterel, was surveyed through a single visit when Dotterel had young chicks.

Results After correcting for missed birds, 750 males were estimated to be breeding in Britain in 1999. An alternative method led to an estimated 510 males. Both methods had their drawbacks – 630 males probably represented the best estimate. Almost 93% of males bred in three regions: central, east and north Highlands. Around a third of surveyed sites were occupied by breeding birds. The national population estimate was significantly higher in 1987/88 but numbers were probably greatest in 1989 and declined in the 1990s. In 1999 Dotterel distribution had contracted to those sites with the highest densities in the late 1980s.

Conclusion It is unlikely that changes in numbers between surveys were due to changes in the British breeding grounds. They may be due to adverse influences away from the breeding grounds or, because Dotterels can move across large distances between breeding attempts, a redistribution of birds away from Scotland to breeding sites elsewhere in the Palearctic.     

Supplementary feeding increases Common Buzzard Buteo buteo productivity but only in poor‐quality habitat

Temporal heterogeneity in the effects of food supply during the breeding season on the productivity of the Common Buzzard Buteo buteo was investigated in a supplementary feeding experiment. Pairs were fed artificially (1) before egg‐laying, (2) after chicks hatched and (3) continuously throughout the season, and compared with (4) unfed controls. Pairs fed before egg‐laying had marginally larger clutches than those not fed, but lay date, egg volume and weight, brood size and hatching success were unaffected. Territorial quality had far greater effects, with pairs nesting in low‐quality habitats (bog, scrub and semi‐natural grassland) laying later and having lower hatching success, smaller broods and fewer fledglings than those in more productive agricultural landscapes. Supplementary feeding after egg hatching neutralized the negative effect of poor habitat, resulting in fed birds having significantly more fledglings. This study emphasizes the importance of food availability when provisioning chicks in suboptimal habitats and has implications for the success of diversionary feeding in reducing game losses to Buzzards.     

Effects of habitat,season, and age on winter fat storage by migrant and resident birds in Jamaica

Most small birds wintering in the tropics should show little subcutaneous fat deposition (SFD), except in habitats where food availability may decline in late winter or, for some resident species, to prepare for incubation or brooding fasts. However, these predictions need re‐examination in light of a new, precise, cross‐validated method to compare SFD among habitats and species. We sampled 170 Nearctic‐Neotropical migrant and 279 resident birds during early and late winter in 1993 and 1994 in Jamaica, West Indies. Habitats, from greatest to least expected availability of insect prey, were (1) mangrove forest, (2) montane/foothills forest and cultivation, (3) dry limestone forest, and (4) acacia scrub. Percent lipid, estimated from multiple‐regression models using visual fat scoring (0–8 scale), total‐body electrical conductivity, and a variety of morphometrics, was categorized by percentile ranks to determine if SFD varied by habitat, season, or age for all species, resident species, migrant species, and several individual species. SFD averaged ~ 13% total mass for all birds, ranging from 8–24% for well‐sampled species. The few bird species in acacia scrub, primarily two facultative long‐distance migrants, averaged ~ 26% lipid content, significantly more than birds in other habitats. Most birds did not vary in SFD in the other three habitats, although Common Yellowthroats (Geothlypis trichas) had greater SFD in dry limestone habitat than in montane habitat. Bananaquits (Coereba flaveola) and Jamaican Euphonias (Euphonia jamaica) in montane habitat, especially in early winter, had higher SFD than other resident species. Contrary to our prediction, adults and juveniles had similar SFD, with the exception of juveniles having more SFD than adults in acacia scrub habitat. Winter fat deposition (or, in some cases, muscle‐protein catabolism) in the tropics may be an overlooked strategy, potentially important as a hedge against fasting for floaters, facultative migrants, some territorial migrants in habitats with seasonal declines in food resources, and some resident species prior to breeding.     

Foraging of lynxes in a managed boreal-alpine environment

Foraging of Eurasian lynxes Lynx lynx was studied with telemetry and snow tracking in central Norway. In all habitats and at all seasons, medium-sized ungulates (roe deer Capreolus capreolus , reindeer Rangifer tarandus and domestic sheep Ovis aries) dominated the diet (81% of ingested biomass estimated from faeces). Mountain hares Lepus timidus and galliform birds comprised the remainder of the diet (15% and 3%, respectively). Lynxes with different life history status did not differ in prey choice, but adult males utilised carcasses of ungulate prey considerably less (16% of the edible parts) than did females with offspring (80%) and subadults (58%.). Forest habitats in lowlands and adjacent to cultivated fields were the most favourable foraging habitats (indexed as the prey encounter rate per km lynx track) primarily owing to the presence of roe deer. Two family groups tracked in winter killed 0.2 ungulate per day. The importance of agricultural land as a foraging habitat and the dominance of livestock in the diet in remoter areas indicate that the lynx has responded to agriculture and reindeer husbandry during the past century by switching from smaff game to ungulates.     

Habitat and diet of young grouse broods: resource partitioning between Capercaillie (Tetrao urogallus) and Black Grouse (Tetrao tetrix) in boreal forests

We compared habitat use and diets of young Capercaillie and Black Grouse broods in a boreal forest in southeast Norway. We used pointing dogs to search for broods (N = 83) in mature “natural” forest types and examined the crop content of 66 chicks 1–9 weeks old. We also measured the abundance of insects in the habitats where broods were found. Although overlapping substantially in both habitat and diets, there were notable differences: Capercaillie broods were more frequently recorded in bilberry-dominated forest types, whereas Black Grouse preferentially used pine bog forest, a more open habitat with little bilberry. Capercaillie chicks ate proportionally more insects, particularly lepidopteran larvae, and insects dominated their diet for a longer period of time (until age 28–29 days) than in Black Grouse (14–15 days). After reaching their peaks, the quantity of insects in the crops declined rapidly especially in Capercaillie, and in one of 2 years this occurred at a time when insects, including larvae, were still abundant in the habitats. Among plant foods, both species ate large amounts of Bilberry (Vaccinium myrtillus) and Bog Whortleberry (V. uliginosum). The main difference between species was a large proportion of both over-wintered and new, not yet ripe, berries of Cranberry (Oxycoccus quadripetalus) in Black Grouse, and a higher proportion of the forb Melampyrum sylvaticum in Capercaillie. The difference in diets reflected their differential use of habitats; the Vaccinium-preferred habitats of Capercaillie were richer in insects, particularly larvae, than the pine bog habitat preferred by Black Grouse. Because insects, especially larvae, comprised a larger proportion of the diet of Capercaillie chicks and chicks of this species need more food to sustain their rapid growth, Capercaillie is likely to be more sensitive to variation in insect food than Black Grouse. Also, by reducing the abundance of bilberry, the main host plant of larvae chick food, clearcutting forestry has negative effects on the brood habitat quality of both species.     

Interactions with Great Skuas Stercorarius skua as a factor in the long‐term decline of an Arctic Skua Stercorarius parasiticus population

Many of the UK’s seabird species have displayed high variation in breeding success since the 1980s, largely due to changes in the availability of Lesser Sandeels Ammodytes marinus, their main prey. During this time, Arctic Skuas Stercorarius parasiticus experienced a rapid decline in the UK and the species has subsequently been placed on the Red List of birds of conservation concern. Although shortage of Lesser Sandeels is likely to be an influential factor, the Arctic Skua’s breeding range overlaps with that of the Great Skua Stercorarius skua, a larger bird with a more varied diet, and interspecific interactions for nesting habitat may exert an additional pressure on Arctic Skua breeding populations. Results from four censuses, spanning 21 years, were used to model habitat use and analyse distributional change in nesting Arctic Skuas at a major colony located on Fetlar, Shetland, Scotland. The decline in Arctic Skuas was not uniform across the island and competition with Great Skuas for nest‐sites appears to have influenced localized breeding distribution. By 2006, Arctic Skuas had been almost entirely excluded from shrub heath, blanket bog and coastal heath habitats, which were identified as preferred habitat in 1986. In 2006, Arctic Skua breeding territories were mainly restricted to one core area of preferred habitat where over 90% nested in high density as this habitat became increasingly occupied by Great Skuas. The more generalist foraging habit of the Great Skua allowed the population to grow rapidly as numbers of the more specialist Arctic Skua decreased during times of low sandeel availability. Our model suggests that both interspecific competition for territories with Great Skuas and food limitation have played important roles in the decline of Arctic Skuas on Fetlar.     

Foraging behaviour of Lesser Sheathbills Chionis minor exploiting invertebrates on a sub-Antarctic island

Summary During winter (May through October) many Lesser Sheathbills Chionis minor at Marion Island in the sub-Antarctic were obliged to leave their preferred foraging habitat in penguin colonies to forage for invertebrates on the island's coastal plain. The study describes factors affecting feeding success, time budgets and predation risk of the sheathbills which exploited these small, patchily dispersed prey. The birds appeared to select prey 1 mm in diameter, and ignore smaller, common invertebrates.Sheathbills were highly selective of foraging habitat. During 17 censuses made through the winter, 97% of the 1,504 birdsightings were at only eight of the 19 available vegetation types. Multiple regression analysis revealed that prey density was the most important criterion in habitat preference, followed by plant canopy height and distance of the habitat from the sea. These variables accounted for 78% of the variance of habitat use. Focal-animal observations in a sample of habitats showed that feeding success was correlated with prey density and distance from the sea. Tall vegetation impeded the locomotion and foraging of sheathbills. The sheathbills reduced predation risk from skuas Catharacta lonnbergi and travelling time by foraging near the shore. The spatial distribution of prey within vegetation types was apparently unimportant in habitat selection.During winter 83% of the sheathbills in the study foraged communally and 98% roosted communally. Flocks occurred only on good quality habitat and flocking probably facilitated habitat selection. Feeding success increased initially with increasing flock size but decreased in flocks greater than 15 birds, which was attributed to localized prey deletions. The sheathbills spent 88% of the daytime foraging; and feeding, looking around and walking comprised 99% of foraging time. Feeding time increased with increasing flock size, looking around decreased but walking was unaffected. Aggression was rare, was unaffected by flock size and did not significantly affect feeding. A probability model showed that sheathbills could greatly reduce predation risk by flocking but the benefits would not improve much in flocks greater than eight birds.The habitat selection, time budgets and feeding success of adults, subadults and juveniles were very similar.The exploitation of terrestrial invertebrates by sheathbills was interpreted as an expansion of the population's trophic niche to tap an underexploited resource on a species-poor island.     

Chick starvation in yellow‐eyed penguins: Evidence for poor diet quality and selective provisioning of chicks from conventional diet analysis and stable isotopes

The link between poor reproductive success and diet was investigated in yellow‐eyed penguins Megadyptes antipodes, by assessing diet at two localities separated by about 30 km: the north coast of Stewart Island where breeding success is low (0.38–0.67 chicks per pair in recent years), and Codfish Island where breeding success is higher (0.96–1.51 chicks per pair), and relating this to published data from South Island localities, where average breeding success was 1.1 chicks per pair. Diet composition, meal sizes and energetic content of meals and prey were determined from stomach contents, and stable isotope analyses of chick down, fledgling feathers and adult blood provided information on diet throughout the fledging period. The high proportion of stomachs that were empty or lacked diagnostic remains reduced sample size considerably, and variability between samples reduced the power to detect significant differences in meal size, proportions of empty stomachs and prey diversity of meals. Energetic content of Stewart Island meals was less than Codfish Island meals, and there was a non‐significant trend for smaller meal sizes and reduced prey diversity among Stewart Island samples. Both localities had lower prey diversity and smaller meals than South Island penguins. Blue cod Parapercis colias accounted for 99% of prey biomass in Stewart Island and 70% in Codfish Island stomach samples, where 27% of prey biomass was opalfish Hemerocoetes monopterygius. Isotopic mixing models carried out on larger sample sizes indicated that opalfish comprised a large proportion of the diet at both locations, with adults selectively provisioning chicks with opalfish while feeding mainly on blue cod themselves. We suggest the large blue cod consumed by Codfish Island and Stewart Island penguins, larger than those consumed by South Island penguins, is difficult to transfer to chicks by regurgitation. Oyster dredging around Stewart Island may have reduced the availability and abundance of alternative prey to Stewart Island penguins.     

Seasonal and regional variations in the feeding habits of the harbour seal, Phoca vitulina, in the Skagerrak and the Kattegat

Studies of the feeding of harbour seals have been carried out at the Tjärnö Marine Biological Laboratory since 1977. The studies are based on fish otoliths found in faeces at seal haulouts. The present paper compares feeding habitats at two different localities. Three families of fish, gadoids, pleuronectids and clupeoids were predominant in the seals' diet at a rocky shore habitat. Pleuronectids made up 75% of the diet at a sandy shore habitat. Temporal variations in feeding habits are also examined. The results indicate that harbour seals are opportunists in their choice of prey species, but some locally abundant species do not appear in their diet.     

Habitat characteristics of breeding Eurasian Whimbrel Numenius phaeopus on Mainland Shetland,Scotland, UK

Capsule: Habitats used by Whimbrel Numenius phaeopus chicks for feeding are significantly different to those used by adults for feeding and nesting.

Aim: To identify habitats used by breeding Whimbrel on Mainland Shetland.

Methods: Fourteen study sites were used to identify three main components of Whimbrel breeding habitats: (i) adult territorial and foraging habitats; (ii) nest site habitats; (iii) chick feeding habitats. The relationship between these components was investigated using principal components analysis.

Results: Habitats used by adults comprised blanket bog dominated by ling heather, cross-leaved heath, common cottongrass, hare’s-tail cottongrass, deergrass and purple moor-grass. There was a thick layer of bryophytes but few forbs. Habitat used for nesting was similar to the general habitat used by adults. The habitats in which Whimbrel chicks foraged were significantly different in structure from the habitats used by adults. The chick feeding areas were characterized by small, wet and often linear features.

Conclusion: Habitat requirements by Whimbrel chicks for foraging differed from those of adult Whimbrel for nesting. Habitat structure is important for chicks and the presence of small, wet linear features may be a limiting component on otherwise apparently suitable adult Whimbrel habitats.     

Foraging behaviour and prey size of the painted stork

The foraging behaviour of painted stork Mycteria leucocephala was studied during 2004–2006 at 14 different sites in the Delhi region, India. Observations were recorded on 131 individuals, including 29 juvenile birds using a video camera. Recordings were also made at the nesting colony in Delhi zoo to study the prey sizes regurgitated to nestlings. The results confirm that the painted stork is a tactile forager and exclusively piscivorous. Foraging group size ranged from 1 to 18 individuals. Per 5 min foot stirring rates in the vegetated habitats were significantly higher than in non-vegetated habitats. The attempt rate and feeding rate in the breeding season were significantly higher than that in the non-breeding season. Prey sizes taken in the breeding season were significantly smaller than those taken in the non-breeding season. About 80% fish fed to the chicks were smaller than 10 cm. Young chicks were offered smaller prey compared with older chicks. The variations in foraging parameters are discussed in relation to habitats and their conservation in the Delhi region.     

Providing nest boxes for hole-nesting birds – Does habitat matter?

Nest boxes are a popular management tool to increase nest site availability for hole-nesting birds, but biological consequences of this technique in different habitats are poorly studied. In our study area in southwestern Estonia, nest boxes for small passerines were set up in deciduous and coniferous woods. Great tits Parus major preferred the food-rich deciduous habitat for breeding, as judged by higher nest-box occupation, earlier egg-laying and larger clutches and eggs. However, in coniferous habitat more and heavier young fledged per nest, and the return rate of both fledglings and adults was higher. We propose two mutually non-exclusive explanations, both related to the maladaptive outcome of the provision of nest boxes: (i) in the preferred habitat, nest boxes caused a supra-optimal breeding density leading to an ecological trap; (ii) boxes drastically improved the non-preferred habitat, but birds were unable to exploit the breeding habitat fully. One should be careful in providing large numbers of artificial nest sites in preferred habitats. Sometimes it would be more preferable to improve less favourable habitats by removing critical constraints.     

Diversity of feeding habitats and diet composition in the turtle doves Streptopelia turtur to buffer loss and modification of natural habitats during breeding season

The approach of the birds to use physical and alimentary resources in degraded and modified natural habitats is an important aspect of their adaptation. This study was undertaken during 2016-2017 at forty habitats in the Moulouya plain, Morocco to examine behavioral diet, habitat use and foraging ecology of turtle dove, Streptopelia turtur. We monitored turtle doves in four major plots namely cereal plots, lucerne farms, apple orchards, and stations in the Ansgmir River covering 40 habitats. Digestive tract contents were also identified and evaluated for 68 Turtle Doves shot by hunters during two consecutive years. The results showed that the turtle doves use a variability of feeding habitats. The cereal cultivation seemed to be more preferable habitat for feeding especially in the month of May, the first breeding phase of the year. But, during the months of August and July, the riverbanks were the preferred habitat for turtle doves. The diet of this species is polyphagous and diverse with a granivorous tendency. Diet analysis showed that soft wheat and barley seeds constituted 44.53% and 38.74% respectively followed by barley seeds with 38.74% and sand stones (9.16%) of the seeds eaten by Turtle Doves. However, moderate proportion of elements (7.32%) remained undefined. All these aspects, including the variability of feeding habitats and the wide diet seem to be an adaptive strategy followed by turtle dove to counter the degradation and the modification of its natural feeding habitats.