Garrulus Glandarius Research Articles

Borreliae in immature Ixodes ricinus (Acari:Ixodidae) ticks parasitizing birds in the Czech Republic.

Of 411 forest birds of 33 species examined near Valtice, Czech Republic, 29% were infested with Ixodes ricinus (L.); 2.2% were parasitized by Haemaphysalis concinna Koch. Borreliae were detected in 5.1 and 11.7% of larval and nymphal I. ricinus, respectively. None of the 13 H. concinna tested was infected. In total, 3.2% of the birds examined were parasitized by I. ricinus immatures infected by borreliae. Borreliae-containing ticks parasitized European robin, Erithacus rubecula (L.); Eurasian blackbird, Turdus merula L.; Blackcap, Sylvia atricapilla (L.); Eurasian chiffchaff, Phylloscopus collybita (Vieillot); Great tit, Parus major L.; and Eurasian jay, Garrulus glandarius (L.). The isolate BR-34 from a nymphal I. ricinus off a Eurasian blackbird had a sodium dodecyl sulfate-polyacrylamide gel electrophoresis protein pattern, reactions to monoclonal antibodies, and fragments of HindIII digested DNA probed with fla and ospA genes that suggested to us that it belongs to the genospecies Borrelia garinii. Free-living birds may be involved in the circulation of B. burgdorferi sensu lato principally as disseminators of infected ixodid ticks to new area.

Spatial patterns of dispersal, seed predation and germination during colonization of abandoned grassland by Quercus petraea and Corylus avellana

Key processes during recruitment of Quercus petraea and Corylus avellana were investigated in abandoned calcareous grasslands and adjacent scrub using the following methods: (1) observation of hoarding animals during the main period of ripening of acorns and hazel nuts, (2) exposition of seeds on the soil surface and in 5–6 cm depth to test differences in predation and germination, and (3) mapping of seedlings in the grasslands. European jays (Garrulus glandarius) and mice were the main disperser of seeds. Jays preferred acorns, whereas the rodents were less selective, but probably more important for dispersal of nuts. The maximum dispersal distance was about 10–20 m for mice and was estimated several hundred metres for jays. Mice collected hoards of several seeds in about 2 cm depth in the soil, whereas jays stored single seeds. Seed predation and probably hoarding by mice were highest under scrub and in unmown grassland, while jays preferred mown sites for hoarding. However, hiding of seeds in the soil reduced losses in all sites. Predation of nuts was slightly less intensive than that of acorns. Seeds of Corylus were more sensitive to desiccation than Quercus, but in both species germination was lower for seeds exposed on the soil surface and in drier sites. Quercus and Corylus were the most abundant woody species in the fallow grasslands, probably due to the effective multi-staged dispersal by jays and mice, whereas wind-dispersed and fleshy-fruited species were less common; the latter restricted to margins of adjacent scrubland. The study provides several examples for discordance in suitability of patches for seeds and seedlings due to different habitat requirements of successive developmental stages. This result emphasizes the need for studies in the multiple stages during recruitment of vertebrate-dispersed plants.

Seasonal patterns of food storing in the Jay Garrulus glandarius

This study investigated seasonal patterns in food consumption and food storage in six captive Jays Garrulus glandarius. In the first experiment, seasonal changes in food‐storing intensity were tested by presenting acorns (oak seeds, Quercus spp.) in spring, summer and autumn. There were no significant differences between the seasons in the amount of food eaten. However, significantly more food was taken and stored in the autumn than in the spring and summer months. In the spring and summer, the acorns were stored between the doorframes, on the ledges of the aviaries and under the bark of branches. In the autumn, Jays also began to hoard underneath the plastic sheeting covering the hard‐board flooring by ripping the polythene to create a hidden cache site. The length of time over which the stored food was left before retrieval increased from summer to autumn. Food storing also occurred in spring and summer but was short term. The second experiment tested whether or not there were seasonal changes in food preference by presenting birds with acorns, peanuts and mealworms in the summer and autumn. More peanuts were eaten, taken and stored in the autumn than in the summer, and, as in the first experiment, significantly more acorns were taken and stored in the autumn. In the autumn, only a few mealworms were eaten before the birds stored acorns and peanuts, whereas in the summer, birds tended to eat most of the mealworms before they began to store. As in the first experiment, items tended to be buried in the ground in the autumn and left for longer periods before retrieval. These results are discussed in relation to the demand that each food type places on the Jay's time.

Population trends of Jays, Magpies, Jackdaws and Carrion Crows in the United Kingdom

Population trends of Jay Garrulus glandarius, Magpie Pica pica, Jackdaw Corvus monedula and Carrion Crow Corvus corone were examined over the period 1964–93 using data from the Common Birds Census. Population growth has been highest in the Magpie and Carrion Crow, although both these have shown a reduction in the rate of growth from the late 1970s. Densities of all 4 corvids have increased on farmland, whereas only Magpie and Carrion Crow have increased in woodland. Population trends were associated with farmland type in all the corvids; the strongest increases were on mixed and grazing farms and the smallest on arable farms. There were strong regional differences in trends within woodland and farmland. Our results are discussed in the context of the long%term changes in corvid populations that have been reported since the start of this century.

Egg-Color Dimorphism and Breeding Success in the Crow Tit (Paradoxornis webbiana)

This study was conducted during the 1988-1989 breeding seasons in Dongguk University Forests (area A) at Namyangju-gun, and during the 1993-1994 breeding seasons in Puyong-ri (area B) at Yangpyong-gun, in Kyonggi-do, South Korea. The eggs of the Crow Tit (Paradoxornis webbiana) had two color types (blue and white) in both areas, but no nests had mixed blue and white eggs. In area A (n = 53), blue clutches (75.5%) were more frequent than white ones (24.5%). In area B (n = 62), the ratio of blue clutches (59.7%) to white ones (40.3%) was not skewed significantly from 1:1. In each area, neither the egg-laying period nor clutch size varied with egg color. Twenty females having two or more successive nests had the same egg color, irrespective of their male mates. However, of seven males that mated with different females, eggs in the nests of two males changed from white to blue. In each area, blue and white clutches tended to be widely distributed throughout the study area. Breeding success was related to nest height above ground, but not to egg color or species of nest tree. Nest predation seems to have been caused mostly by Eurasian Jays (Garrulus glandarius) in high nests, by Common Cuckoos (Cuculus canorus) in midlevel nests, and by snakes (Natrix) in low nests.

Non-Territorial Behaviour and Habitat Selection in the Jay Garrulus glandarius in a Mediterranean Coastal Area during the Reproductive Period

Spring territorial behaviour and habitat selection of the Jay Garrulus glandarius were investigated in two study areas in the Maremma Natural Park (Central Italy). Seven birds in 1990 and seven in 1991 were trapped and subsequently radio-tracked. Incremental area plots and the analysis of auto-overlap showed that most of the Jays did not have fixed home ranges, and that these overlapped greatly. Furthermore, many untagged Jays were seen inside the home ranges of the tagged ones and one pair of Jays successfully reproduced in 1991 inside other Jays' home ranges. No aggressive interactions were observed. These data seem to suggest that the Jays in Maremma do not show territorial behaviour. Home range sizes at one study area (Faunistico) were larger than in the other area (Pratini) (on average 36 ha versus 5 ha). This could depend on the higher habitat diversity or lower habitat quality of the first area. Habitat use differed between the areas. At Pratini the maquis scrub was positively selected whereas the olive grove was avoided; at Faunistico the maquis, the olive grove and the cultivated fields were avoided whereas the meadows with scattered trees and the open scrub were positively selected. The non-territorial behaviour of the Jays in the Maremma Natural Park may be determined by several local factors, such as resource abundance, high density of birds, low reproductive rates and food partly being collected outside the maquis. In particular, both in the case of resource abundance and in that of high density of birds, the cost of sharing resources would be less than the cost of defending the territory against all intruders and a non-territorial system would indeed be expected.

Storage of stones by Jays Garrulus glandarius

The aims of this study were to test whether or not Jays Garrulus glandarius store stones and, if so, to examine the conditions under which they store stones. By directly observing the behaviour of five captive Jays that were housed individually in flight cages, we found that stones were stored only in the absence of food items or when food items were no longer available to store and that there was a strong preference for storing stones that resembled acorns in both size and appearance (in terms of colour, shape and smoothness of the surface) and were undamaged rather than heavily chipped. These results are discussed in terms of Tinbergen's classic ethological model in which animals respond selectively to certain key features and ignore other features of the stimulus.

Memory for spatial and object-specific cues in food-storing and non-storing birds

Two storer/non-storer pairs of species, marsh tit (Parus palustris)/blue tit (P. caeruleus) and jay (Garrulus glandarius)/jackdaw (Corvus monedula) were compared on a one-trial associative memory task. In phase I of a trial birds searched for a reward in one of four feeders which differed in their trial-unique spatial location and object-specific cues. Following a retention interval, the birds had to return to the same feeder to obtain a further reward. In control trials the array of feeders was unaltered, whilst in dissociation tests it was transformed to separate spatial location and object-specific cues.

Growth and Survival after Cotyledon Removal in Quercus robur Seedlings, Grown in Different Natural Soil Types

The effect of cotyledon removal on oak (Quercus robur L.) seedlings was studied in an experiment. In nature, acorns are dispersed by a predator, jay (Garrulus glandarius) which hoards acorns in autumn and hide them in the ground. These acorns may germinate in spring and after seedling establishment the birds locate young seedlings and remove and eat the cotyledons. Seedlings of oak were grown in field pots during two growing seasons. Cotyledons were removed from half of the plant material at the time of leafing in the first year. The seedlings were grown in six natural soils with different texture and nutrient status. Effects of soil type were more important than presence or absence of cotyledon on the growth of the oak seedlings (...)

Isolation and primary structure of a novel avian pancreatic polypeptide from five species of Eurasian crow

Chicken pancreatic polypeptide is the prototype of the neuropeptide Y (NPY)/PP superfamily of regulatory peptides. This polypeptide was appended the descriptive term avian, despite the presence of some 8600 extant species of bird. Additional primary structures from other avian species, including turkey, goose and ostrich, would suggest that the primary structure of this polypeptide has been highly-conserved during avian evolution. Avian pancreatic polypeptides structurally-characterised to date have distinctive primary structural features unique to this vertebrate group including an N-terminal glycyl residue and a histidyl residue at position 34. The crow family, Corvidae, is representative of the order Passeriformes, generally regarded as the most evolutionarily recent and diverse avian taxon. Pancreatic polypeptide has been isolated from pancreatic tissues from five representative Eurasian species (the magpie, Pica pica; the jay, Garrulus glandarius; the hooded crow, Corvus corone; the rook, Corvus frugilegus; the jackdaw, Corvus monedula) and subjected to structural analyses. Mass spectroscopy estimated the molecular mass of each peptide as 4166 ± 2 Da . The entire primary structures of 36 amino acid residue peptides were established in single gas-phase sequencing runs. The primary structures of pancreatic polypeptides from all species investigated were identical: APAQPAYGDDAPVEDLLRFYNDLQQYLNVVTRPRY. The peptides were deemed to be amidated due to their full molar cross-reactivity with the amide-requiring PP antiserum employed. The molecular mass (4165.6 Da), calculated from the sequences, was in close agreement with mass spectroscopy estimates. The presence of an N-terminal alanyl residue and a prolyl residue at position 34 differentiates crow PP from counterparts in other avian species. These residues are analogous to those found in most mammalian analogues. These data suggest that the term avian, appended to the chicken peptide, is no longer tenable due to the presence of an Ala 1, Pro 34 peptide in five species from the largest avian order. These data might also suggest that, in keeping with the known structure/activity requirements of this peptide family, crow PP should interact identically to mammalian analogues on mammalian receptors.

Spatial memory in a food storing corvid

This work suggests how food storing corvids use spatial memory to relocate caches, and how they can do this after some landmarks surrounding caches have become hidden due to leaf fall, snow fall or plant growth. Experiments involved training European jays (Garrulus glandarius) to find buried food, the location of which was specified by an array of 12 landmarks. Tests were then performed with the array rotated, or with certain landmarks removed from the array. The main findings were: (1) birds primarily remembered the position of the goal using the near tall landmarks (15–30 cm from the goal and 20 cm high); (2) birds obtained a sense of direction both from the landmark array and something external to the array; (3) birds did not use smell or marks in the surface of the ground to find the goal. Memory of near tall landmarks is likely to be functional for these birds since (a) nearer landmarks provide a more accurate fix, and (b) taller landmarks are less likely to be completely obscured by snow fall, leaf fall or intervening vegetation. The work also demonstrates the use of G.I.S. software for the analysis and representation of animal search patterns.

Food storing and the hippocampus in corvids: amount and volume are correlated

The volume of the hippocampal region (dorsomedial cortex) relative to body mass was measured in seven species of corvid (red-billed blue magpie, Cissa erythrorhyncha; European crow, Corvus corone; rook, C. frugilegus; jackdaw, C. monedula; jay, Garrulus glandarius; magpie, Pica pica; and Alpine chough, Pyrrhocorax graculus). The species studied differ in the extent to which they store food, and the results showed that there is a positive correlation between the estimated amount of food-storing behaviour and the relative volume of the hippocampus among the seven species. For two of the species, magpie and jackdaw, intraspecific variation was analysed. These two species show a sex difference in relative hippocampal volume (males larger than females), although there are no reports of sex differences in storing behaviour. In the magpie, which stores food regularly, hippocampal volume relative to body mass is positively related to relative volume of the rest of the telencephalon, whereas in the jackdaw, which rarely stores food, there is no relation.

Corvid Density and Nest Predation in Relation to Forest Fragmentation: A Landscape Perspective

The abundance and distribution of corvids (Common Raven, Corvus corax; Hooded Crow, C. corone; Jackdaw, C. monedula; Black—billed Magpie, Pica pica; and European Jay, Garrulus glandarius) were studied across a gradient from a landscape dominated by agricultural land to a landscape dominated by forest in south—central Sweden. The total density and the predation rate on dummy nests increased as the proportion of agricultural land increased. This supports the suggestion that the density of corvids increases as forest becomes fragmented and intermixed with agricultural land, causing an increase in nest predation in small forest fragments. However, the different species responded differently to the proportion of forest in the landscape. The two forest—living corvids, the Jay and Raven, were absent from small forest fragments in a matrix of agricultural land and mainly preyed upon dummy nests inside the large forest fragments. Thus, both of these species were habitat specialists restricted to forests. Three corvids basically inhabit agricultural land, the Hooded Crow, Jackdaw, and Magpie. The Jackdaw and the Magpie showed a strong preference for agricultural land and they mainly preyed upon dummy nests in agricultural land. On the other hand, the density of Hooded Crows was higher in landscapes with a mixture of agricultural land and forest than in landscapes dominated by either agricultural land or forest, indicating a use of both agricultural land and forest. Further, Hooded Crows regularly preyed upon nests in both forest habitat and agricultural land; it is a habitat generalist. Therefore, the Hooded Crow was the most important species in the corvid family, causing increased predation pressure close to forest—farmland edges and in small forest fragments surrounded by agricultural land.

Acorn Preference of Urban Blue Jays (Cyanocitta cristata) during Fall and Spring in Northwestern Arkansas

We censused 26 acorn-bearing trees of six oak species for Blue Jays (Cyanocitta cristata) during fall of 1985 on the University of Arkansas campus. The following spring we presented six piles, each containing 20 acorns from a different oak species, to free-ranging jays to determine acorn preference in spring. Trees censused and acorns presented were from both black oak (BO) and white oak (WO) subgenera, which differ in size, percent fat, tannin content, and germination time. In fall, Blue Jays were observed removing acorns from three species of oaks with small acorns, particularly those of willow oaks (BO, Quercus phellos), and were rarely observed in trees of three other oaks with large acorns. When offered a choice of acorns from six oak species in spring, Blue Jays showed a preference, based on Ivlev's electivity index, for small acorns, particularly those of pin oaks (BO, Q. palustris), and an avoidance of large acorns. Thus, small size appears to be an important trait associated with acorn preference in Blue Jays. Acorns of the introduced English oak (WO, Q. robur), which are preferred by Euorpean Jays (Garrulus glandarius) (Bossema 1979), also were avoided in spring by Blue Jays, suggesting that familiarity may be a general component of acorn selection by jays.

Density, Range Size and Diet of the European Jay Garrulus glandarius in the Maremma Natural Park, Tuscany, Italy, in Summer and Autumn

Density, Range Size and Diet of the European Jay Garrulus glandarius in the Maremma Natural Park, Tuscany, Italy, in Summer and Autumn

Responses of breeding Reed Warblers Acrocephalus scirpaceus to mounts of Sparrowhawk Accipiter nisus, Cuckoo Cuculus canorus and Jay Garrulus glandarius

Mounts of a Cuckoo Cuculus canorus, a Sparrowhawk Accipiter nisus and a Jay Garrulus glandarius were presented at nests of Reed Warblers Acrocephalus scirpaceus at all breeding stages. Response strength could best be classified according to approach distance (to the mount) and vocalizations used. Warblers reacted much more aggressively to a mount on the nest than to one 3 m adjacent; they approached much more closely, were less likely to sing but often gave a frenzied‐sounding rasp (which was never given to an adjacent mount). Reaction was more aggressive to a Cuckoo, which was often attacked, than to a Sparrowhawk, of which they were wary; response to a Jay was intermediate. Reaction was more aggressive after the clutch had been completed than before. After the brood had fledged, parents still responded strongly to the Jay and Sparrowhawk, but responded to the Cuckoo only briefly before ignoring it. These results are consistent with the Reproductive Value‐Stimulus Value hypothesis. They also demonstrate that Reed Warblers can tell Cuckoos from Sparrowhawks, as can many non‐host species. The close resemblance of these two species is often suggested to be mimicry of the Sparrowhawk by the Cuckoo but, if this is so, it is not successful. Alternatively, the similarity could be mimicry to reduce predation on the Cuckoos themselves, a chance resemblance, or due to similar selective forces acting on both species, as each would presumably benefit from reduced conspicuousness.

Despotic Distribution, Unequal Reproductive Success, and Population Regulation in the Jay Garrulus Glandarius L.

A population of European Jays (Garrulus glandarius L.) in south—central Sweden occupied territories in most forest habitats. However, there was a strong preference for dense forest, characterized by trees older than 10 yr and a composition of >30% Norway spruce (Picea abies Karst.). Individuals having territories in this preferred habitat exhibited the highest breeding success. This supports the Fretwell—Lucas model of ideal—despotic distribution. Differences in nest predation, and perhaps also in food abundance and adult predation, caused higher breeding success in forest dominated by Norway spruce than in other forests. Despots were not distinguished by size, but age might be more important in long—lived species like the Jay. Territoriality means that certain individuals monopolize some resources at the expense of other individuals, which results in unequal resource partitioning. Following current ideas of population regulation due to unequal resource partitioning in a heterogeneous environment, I discuss the effect of having the preferred habitat unequally divided among individuals, which will result in a density—dependent breeding output, and also suggests a possible system of population regulation.

Seasonal Changes in Ranging Behaviour and Territoriality in the European Jay Garrulus g. glandarius

This 5-yr study analyses home-range sizes in a population of European Jays in southernmost Sweden in relation to population density and breeder status. Homerange sizes were measured by radio-tracking during the pre-breeding and breeding periods. The home-range sizes of individual Jays changed with the onset of breeding. In years with a high number of adult birds at the beginning of the breeding season, home-ranges were compressed and, conversely, during low density years they were enlarged. Whereas home-range size was positively related to population density during the pre-breeding period, it showed a negative relation to density during breeding. Non-breeders had larger home-ranges than breeders at all breeding population densities. Intrusions by neighbours were more frequent during pre-breeding. These results suggest that an increase in territorial behaviour by resident Jays occurs during the breeding period, probably owing to increased competition over resources important to reproduction.

Use of recombinant vaccinia-rabies glycoprotein virus for oral vaccination of wildlife against rabies: innocuity to several non-target bait consuming species.

The pathogenicity of a vaccinia recombinant virus expressing the rabies glycoprotein (VVTGgRAB) was tested in several wild animal species which could compete with the natural rabies host, the red fox (Vulpes vulpes) in consuming vaccine baits in Europe. The following species were included in this study: wild boar (Sus scrofa), Eurasian badger (Meles meles), wood mouse (Apodemus sylvaticus), yellow-necked mouse (Apodemus flavicollis), bank vole (Clethrionomys glareolus), common vole (Microtus arvalis), field vole (Microtus agrestis), water vole (Arvicola terrestris), common buzzard (Buteo buteo), kestrel (Falco tinnunculus), carrion crow (Corvus corone), magpie (Pica pica) and jay (Garrulus glandarius). During the observation period, the 107 animals given the VVTGgRAB vaccine orally did not show any clinical signs. Daily monitoring for 28 days and postmortem examination did not result in the detection of pox lesions in the oral mucosa or the skin in mammals or the unfeathered portions of birds. VVTGgRAB seems to multiply in the mammalian species tested, since rabies seroconversion was observed in all of them. Birds failed to develop demonstrable rabies virus-neutralizing antibody. A seroconversion against vaccinia virus was observed in two of four wild boars. Serological results obtained in badgers and wild boars also demonstrates the absence of direct or indirect horizontal transmission of the recombinant virus. The potential of the recombinant virus for the immunization of badgers against rabies also was investigated. Only 50% of the badgers orally administered with 1 x 10(8.3) TCID50 of this vaccine were protected against rabies.

A Comparison of Losses in Artificial and Naturally Occurring Capercaillie Nests

During 1980-84 I studied the fates of 821 artificial nests, 96 naturally occurring capercaillie (Tetrao urogallus) nests, and 12 black grouse (T. tetrix) nests at Varaldskogen, Norway. In 4 of the 5 years artificial nests with poor cover had higher loss rates than natural capercaillie nests. In 1981 natural capercaillie nests had a higher loss rate than artificial nests with poor cover. In 1981 the loss rate of natural capercaillie and black grouse nests increased as the season progressed, while the loss rate of artificial nests was constantly low. Capercaillie nests were probably detected by scent by predators most years, while predators oriented mainly by sight probably robbed most artificial nests. Loss of artificial nests was not an index to the loss of capercaillie nests. In artificial nests the losses depended on nest cover; however, natural capercaillie nests in poor cover had higher losses than nests in good cover only during 1 year. J. WILDL. MANAGE. 52(1):123-126 Many bird species suffer high nest losses. Because artificial nests are easy to make they have been used to study the causes of nest losses and predator hunting strategies (Goransson et al. 1975, Boag et al. 1984, Angelstam 1986). In some studies (Henry 1969, Dzieciolowski and Matuszewski 1982, Miiller 1985) results from experiments with artificial nests have been extrapolated to natural nests. This has been done even though the relation between losses in natural versus artificial nests has not been properly evaluated. I compared nest losses of artificial nests with losses of naturally occurring capercaillie and black grouse nests (unprepared depressions in the ground) to determine if predation on artificial nests could be used as an index to predation on natural nests. The experiment was designed to separate predators that used scent from those that mainly relied on sight to locate the prey. This study was financed by the Norwegian Directorate of Nature Conservation and T. Gotaas Fund. The study was conducted in close collaboration with P. Wegge. His help and advice were essential. B. B. Larsen, L. Kastdalen and the rest of the staff at Varaldskogen Field Station assisted in the field. K. E. Erikstad, N. C. Stenseth and P. Angelstam gave valuable comments about the manuscript. S. BondrupNielsen and R. W. Dimmick have kindly improved the language. STUDY AREA This study was conducted at Varaldskogen (60010'N, 12030'E) in Hedmark County, Norway, situated in the Middle Boreal Zone (Abrahamsen et al. 1977). Norway spruce (Picea abies) and Scots pine (Pinus silvestris) were the dominating tree species, and blueberry (Vaccinium spp.) and heather (Calluna vulgaris) dominated the ground layer. Potential egg-predators were red fox (Vulpes vulpes), pine marten (Martes martes), badger (Meles meles), stoat (Mustela erminea), weasel (Mustela nivalis), hooded crow (Corvus corone cornix), common raven (C. corax), and jay (Garrulus glandarius).