共查询到20条相似文献,搜索用时 15 毫秒
1.
R. P. Wilson B. Alvarrez L. Latorre D. Adelung B. Culik R. Bannasch 《Polar Biology》1998,19(6):407-413
The movements of gentoo penguins (Pygoscelis papua) in Antarctica were studied by equipping a total of 37 birds captured at Ardley Island, South Shetlands between December
1991 and May 1996 with position-determining devices. Information on area usage was derived from 20 of these devices and covered
the incubation period (N = 3 birds), the chick-rearing period (N = 14 birds) and the over-wintering period (N = 3 birds). During incubation birds only ventured further than 50 km from the colony 20% of the time and no individual ranged
further than 200 km from the colony. In contrast, no individuals attending chicks ranged further than 16 km from the colony.
During winter the maximum distance ranged from the colony was 268 km. Mean distances between the birds and the colony were
80, 81 and 127 km. Individual birds tended to associate with one spot, making short (10 day) forays away before returning
to nodal areas. The ranging capacity of gentoo penguins appears considerably less than that of sympatric congeners and may
reflect the ability of gentoo penguins to dive deeper and thus exploit prey not accessible to congeners.
Received: 1 October 1997 / Accepted: 3 February 1998 相似文献
2.
In spite of recent theoretical interest, few field studies have addressed the links between individual behavioral decisions
and population distribution. This work analyzes the foraging behavior of individuals and the spatial distribution of a population
of blue tits (Parus caeruleus) just before the main breeding season, when blue tit foraging was not affected by central-place or flocking behaviors. The
study was carried out in open holm oak Quercus ilex woodlands (dehesas) that are patchy for canopy-foraging birds because of the scattered arrangement of trees. Residence time on each tree was
not correlated either with previous flight time or with prey abundance in trees. Flight distances between trees were larger
than average distances estimated in random samples of holm oaks taken close to foraging birds. Trees were not selected by
birds on the basis of their expected energy costs and rewards. Bird abundance was not related to food availability in trees
or to tree size across dehesas. However, bird abundance was strongly correlated with tree density and with the availability of tree holes for nesting, to
the extent that the proportion of tits matched the proportions of both tree abundance and hole abundance across study plots.
Overall, neither the behavior of individuals nor the distribution of the population of blue tits corresponded with food resources,
which appeared superabundant; instead, tits appeared to behave and be distributed according to the distribution of structural
resources such as trees and tree holes for nesting.
Received: 18 August 1996 / Accepted: 14 March 1997 相似文献
3.
It is well known that androgen-dependent sexual behaviors in male mammals and birds are inhibited by exogenous progesterone (P). However, recent research on male whiptail lizards (Cnemidophorus inornatus) indicates that P can stimulate sexual and copulatory behavior. We report here both antiandrogenic and synandrogenic actions of P on sexual behavior in males of another reptile, the green anole lizard (Anolis carolinensis). Earlier reports on birds and mammals are reviewed and discussed in relation to a possible physiological role of P in influencing sexual behavior in male vertebrates. 相似文献
4.
Genetic analysis of interspecific hybridisation in the world’s only Forbes’
parakeet (Cyanoramphus forbesi) natural population 总被引:1,自引:1,他引:0
Chi-hang Chan Kaye N. Ballantyne Hilary Aikman Denise Fastier Charles H. Daugherty Geoffrey K. Chambers 《Conservation Genetics》2006,7(4):493-506
Genetic introgression from Chatham Island Red-crowned parakeet (Cyanoramphus novaezelandiae chathamensis) is a long-standing problem in the conservation of the rare Forbes’ parakeet (C. forbesi) on Mangere Island, New Zealand. Microsatellite genotypes, mitochondrial DNA sequences, and morphological markers have been applied to study the situation. An extensive history of hybridisation was detected in the single remaining Forbes’ parakeet population, where no less than 81% of all birds screened are considered hybrids. Genetic markers showed that a large proportion of birds identified as Forbes’ parakeets by crown plumage are cryptic hybrids. Only a small proportion of birds with Forbes’ parakeet morphotype were found to be genetically distinct from Chatham Island Red-crowned parakeets using microsatellite and mitochondrial DNA assignment tests, but these still represent an Evolutionarily Significant Unit (ESU) for conservation. 相似文献
5.
Test of a digestion optimization model: effect of variable-reward feeding schedules on digestive performance of a migratory bird 总被引:1,自引:0,他引:1
Birds on migration often alternate between feeding and nonfeeding periods, in part because food resources may be patchily
distributed and in part because birds on migration may adopt a risk-prone foraging strategy characterized by selection of
variable rather than constant food rewards. Optimal digestion models predict that increases in intermeal interval like those
encountered by some migratory birds should result in longer retention time of digesta and higher digestive efficiency if birds
are maximizing their rate of energy intake. We tested these predictions by comparing residence time of digesta and extraction
efficiency of lipid for captive yellow-rumped warblers (Dendroica coronata) feeding adlibitum and when we added intervals of time when the birds received no food. We increased the likelihood that the warblers were maximizing
their rate of energy intake by increasing light levels during spring to induce hyperphagia (treatment birds (16L:8D light:
dark cycle) ate 2.13 ± 0.14 g dry food day−1 (n = 8) while control birds (10L:14D) ate 1.25 ± 0.03 g dry food day−1 (n = 6)). Treatment birds offered food only every other 2–3 h ate 50% more during the 4-h test period than when they were always
feeding adlibitum. Despite these differences in food intake, extraction efficiency of glycerol trioleate remained high and constant (93%),
and mouth-to-anus total mean retention time (TMRT) did not change (overall mean: 54.8 ± 6.0 min). Residence time of lipid
in the stomach increased whereas residence time of lipid in the intestine decreased when birds fed only every other 2–3 h
compared to when birds always fed ad libitum. None of the results were consistent with the predictions of the optimal digestion model unless we assume that birds were
minimizing their feeding time rather than maximizing their rate of energy gain. Furthermore, the ability of yellow-rumped
warblers to maintain high extraction efficiency with no change in TMRT suggests some spare digestive capacity when food intake
increases by as much as 50%.
Received: 14 June 1997 / Accepted: 20 November 1997 相似文献
6.
Energy demands of migration on red-eyed vireos, Vireo olivaceus 总被引:4,自引:0,他引:4
We studied the behavior of red-eyed vireos (Vireo olivaceus)includingtheir length of stopover, rate of mass change (lipid deposition),and foraging behaviorin relation to energy demand aftertheir spring migration across the Gulf of Mexico. We labeledeach foraging bird as lean or fatbased on the average condition of birds captured on that day.Lean birds stayed longer and were more likely to gain mass duringtheir stopover than birds that arrived with unmobilized fatreserves. Several aspects of the birds' foraging behavior variedin relation to mean body mass on observation days: Lean migrants(1) broadened their use of microhabitat but not their verticaldistribution of foraging locations, (2) expanded their feedingrepertoire, (3) moved at a higher mean velocity while averagingthe same frequency of foraging movements, and (4) increasedtheir degree of turning after a feeding attempt. We suggestthat the gain of mass by fat-depleted birds is a compensatoryresponse to energy demand mediated by changes in foraging behavior. 相似文献
7.
Gunnhild Marthinsen Liv Wennerberg Roar Solheim Jan T. Lifjeld 《Conservation Genetics》2009,10(4):923-933
The snowy owl (Bubo scandiacus) is a nomadic species with a circumpolar distribution. It has recently declined in the western Palearctic and may thus be
worthy of special consideration for conservation. We investigated genetic structure in three well separated geographic regions
within the snowy owls’ breeding range. We sequenced two mitochondrial genes; the control region and cytochrome b, and two Z-chromosome introns; VLDLR-9 and BRM-15. We found no phylogeographic structure among the sampled regions, indicating
high levels of gene flow in the recent past and possibly still today. Intra-population diversity did not vary between regions
for the control region, but for Cyt b, North American birds had higher haplotype diversity than Scandinavian and eastern Siberian birds. Western Palearctic birds
do not seem to be genetically deprived or inbred. Genetic diversity in the snowy owl was not lower than Scandinavian populations
of three other owl species: tawny owls (Strix aluco), Tengmalm’s owls (Aegolius funereus) and eagle owls (Bubo bubo). 相似文献
8.
Rebecca L. Bentzen Abby N. Powell Laura M. Phillips Robert S. Suydam 《Polar Biology》2010,33(8):1075-1082
Incubating birds balance their energetic demands during incubation with the needs of the developing embryos. Incubation behavior
is correlated with body size; larger birds can accumulate more endogenous reserves and maintain higher incubation constancy.
King eiders (Somateria spectabilis) contend with variable and cold spring weather, little nesting cover, and low food availability, and thus are likely to rely
heavily on endogenous reserves to maintain high incubation constancy. We examined the patterns of nest attendance of king
eiders at Teshekpuk and Kuparuk, Alaska (2002–2005) in relation to clutch size, daily temperature, and endogenous reserves
to explore factors controlling incubation behavior. Females at Kuparuk had higher constancy (98.5 ± 0.2%, n = 30) than at Teshekpuk (96.9 ± 0.8%, n = 26), largely due to length of recesses. Mean recess length ranged from 21.5 to 23.7 min at Kuparuk, and from 28.5 to 51.2 min
at Teshekpuk. Mean body mass on arrival at breeding grounds (range; Teshekpuk 1,541–1,805, Kuparuk 1,616–1,760), and at the
end of incubation (Teshekpuk 1,113–1,174, Kuparuk 1,173–1,183), did not vary between sites or among years (F < 1.1, P > 0.3). Daily constancy increased 1% with every 5°C increase in minimum daily temperature (β
min = 0.005, 95% CI 0.002, 0.009). Higher constancy combined with similar mass loss at Kuparuk implies that females there met
foraging requirements with shorter recesses. Additionally, females took more recesses at low temperatures, suggesting increased
maintenance needs which were potentially ameliorated by feeding during these recesses, indicating that metabolic costs and
local foraging conditions drove incubation behavior. 相似文献
9.
I. Giladi B. Pinshow 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》1999,169(4-5):311-318
Body water conservation is important in flying birds because the very high metabolic demands and heat dissipation requirements
during flight depend on plasma-volume integrity. Wind tunnel experiments and theoretical model predictions show that evaporative
water loss (EWL) depends on air temperature (T
a) and water vapor density (ρa), but these relationships have not been examined in free-flying birds. The contribution of excretory water loss to the total
water loss of a flying bird is thought to be negligible but this assumption is untested. To study the dependence of water
losses on environmental conditions in free-flying birds and to quantify the contribution of excretory water loss to total
water loss, we estimated evaporative and excretory water losses in 16 trained, free-flying tippler pigeons (Columba livia, 250–340 g). We collected excreta by attaching a light latex, water-impermeable receptacle around each bird's vent. By gravimetry,
we measured evaporative and excretory water losses of birds for eight flights at different T
as and compared flying to resting (control) birds for two of these flights. EWL was constant with respect to T
a when less than 15 °C, and increased with increasing T
a above 19 °C, indicating that evaporative cooling was invoked when the heat load increased. EWL increased with increasing
ρa, possibly due to the strong correlation between ρa and T
a. Excretory water loss was independent of ρa or T
a and averaged almost 10% of the total water loss. Measurements of EWL made on pigeons during wind tunnel experiments and previous
free-flight studies are consistent with our free-flight measurements made at similar T
a
s.
Accepted: 13 April 1999 相似文献
10.
Lloyd Demetrius 《Bulletin of mathematical biology》1968,30(1):117-122
In previous studies of (M,R) (Rosen, 1961; Demetrius, 1966), it was assumed that changes in the structure of (M,R) which were induced by environmental alternations occurred without error. Here, the effect of both “genetic” and “metabolic”
malfunctions on the behavior of (M,R) is examined and a subclass of these systems whose behavior is invulnerable to such errors is specified. 相似文献
11.
Studies focused on how prey trade-off predation and starvation risk are prevalent in behavioral ecology. However, our current
understanding of these trade-offs is limited in one key respect: we know little about the behavior of predators. In this study,
we provide some of the first detailed information on temporal patterns in the daily hunting behavior of bird-eating Accipiter hawks and relate that to their prey. During the winters of 1999–2004, twenty-one sharp-shinned hawks (A. striatus) and ten Cooper’s hawks (A. cooperii) were intensively radio tracked in rural and urban habitats in western Indiana, USA. Cooper’s hawks left roost before sunrise
and usually returned to roost around sunset, while sharp-shinned hawks left roost at sunrise or later and returned to roost
well before sunset. An overall measure of Cooper’s-hawk-induced risk (a composite variable of attack rate and activity patterns)
generally reflected the timing of prey activity, with peaks occurring around sunrise and sunset. In contrast, risk induced
by the smaller sharp-shinned hawk did not strongly reflect the activity of their prey. Specifically, an early morning peak
in prey activity did not correspond to a period with intense hawk activity. The lack of early morning hunting by sharp-shinned
hawks may reflect the high risk of owl-induced predation experienced by these hawks. The net effect of this intraguild predation
may be to “free” small birds from much hawk-induced predation risk prior to sunrise. This realization presents an alternative
to energetics as an explanation for the early morning peak in small bird activity during the winter. 相似文献
12.
On the uptake of ornithogenic products by plants on the inland mountains of Dronning Maud Land, Antarctica, using stable isotopes 总被引:2,自引:2,他引:0
Breeding snow petrels (Pagodroma nivea) may be a major source of nutrients for the ecosystems on the inland nunataks (mountain outcrops) of continental Antarctica.
To test this theory, the δ15N and δ13C values of soil and plants (moss, lichen and algae) from 11 nunataks with and without breeding snow petrels in northwestern
Dronning Maud Land were compared. High δ15N values in all samples from nunataks with breeding birds provide a strong indication of the presence of breeding birds, as
well as the use of bird-derived nitrogen by the plants of these ecosystems. The δ13C values showed little difference between the nunataks and are not a useful indicator of bird effects on ecosystem development.
Received: 3 March 1997 / Accepted: 30 March 1998 相似文献
13.
During autumn migration (September to December), brent geese (Branta b. bernicla) and wigeon (Anas penelope) feed on the seagrass Zostera noltii in the nearshore, upper tidal zone leeward of the island of Sylt (eastern North Sea). To graze on leaves and shoots above
the sediment and on rhizomes and roots below, these birds reworked the entire upper 1 cm layer of sediment eight times within
this 3-month period. In addition, brent geese excavated pits 3–10 cm deep by trampling in order to feed on below-ground phytomass.
About 12% of the seagrass beds became pitted to an average depth of 4.5 cm. Using net exclosures, it was estimated that birds
removed 34 g dry weight m–2 of above-ground and 28 g of below-ground phytomass. This corresponds to 45% of the phytomass in September. Of the overall
loss of phytomass from September to December, 63% was caused by birds. Roughly half of the leaves fell off anyway until December
and the other half were taken by the birds. Below the ground, phytomass remained almost constant where birds were excluded,
while with birds phytomass of rhizomes and roots was halved. In spite of this strong effect, in the next vegetation period
the blade density was lower at former exclosure sites compared to the ambient seagrass bed. The underlying process seems to
be a self-inhibition of dense overwintering seagrass by mud accretion. Assuming our experimental results can be scaled up
to the entire seagrass bed, we hypothesize that in the sheltered upper intertidal zone, seasonal erosion caused by herbivorous
geese and ducks is necessary for the persistence of Z. noltii.
Received: 7 January 1999 / Received in revised form: 23 August 1999 / Accepted: 25 August 1999 相似文献
14.
15.
Roman B. Ho?yński 《Journal of Ornithology》2009,150(1):307-309
The “reverse migration hypothesis” as the explanation for the vagrancy of Far Eastern birds in Europe is commented on. It
is concluded that, as the postulated switch of 180° along a great circle line would lead the eastern or even central Siberian
birds to North America rather than to Europe, the application of the “reverse migration hypothesis” to them seems untenable
(which, however, does not preclude its plausibility in case of transatlantic, southern European, or even southwestern Siberian
vagrants). On the other hand, patterns of appearance of the Turdus [naumanni] superspecies (Machalska et al. 1967) suggest the relationship of the phenomenon of vagrancy to post-breeding nomadic movements and/or periodical invasions of
non-migrating species. 相似文献
16.
Egeler O Williams TD Guglielmo CG 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2000,170(2):169-174
Long-distance migration in birds is characterized physiologically by periods of rapid fattening and lipogenesis, and increased
desaturation of fatty acids stored in adipose tissue. We investigated seasonal, age- and sex-related differences in activities
of two lipogenic enzymes, fatty acid synthase and Δ9-desaturase, in relation to migration in the small, Arctic-nesting western sandpiper (Calidris mauri). Migration, and associated lipogenesis and fattening, involved marked upregulation of these enzymes in this species. However,
this increase in enzyme activity was only seen in actively migrating birds during spring migration, when fatty acid synthase
and Δ9-desaturase levels increased by 53% and 113%, respectively, compared to non-migrating birds. There was no change in fatty
acid synthase enzyme activity during the premigration period, even though body mass of adult birds increased significantly
during this period. Similarly, there was no increase in Δ9-desaturase activity during premigration, despite the fact that birds increase the proportion of monounsaturated fatty acids
in their fat stores at this time. We suggest that upregulation of lipogenic enzymes is required to support high rates of mass
gain (0.4 g day−1) during short (1–4 day) periods at stop-over sites. However, slower rates of mass gain (0.09 g day−1) over several weeks prior to migration can be achieved without any increase in tissue-specific enzyme activity.
Accepted: 29 November 1999 相似文献
17.
Susan I. Jarvi Dennis Triglia Alexis Giannoulis Margaret Farias Kiara Bianchi Carter T. Atkinson 《Conservation Genetics》2008,9(2):339-348
We cultured avian pox (Avipoxvirus spp.) from lesions collected on Hawai‘i, Maui, Moloka‘i, and ‘Oahu in the Hawaiian Islands from 15 native or non-native birds
representing three avian orders. Phylogenetic analysis of a 538 bp fragment of the gene encoding the virus 4b core polypeptide
revealed two distinct variant clusters, with sequences from chickens (fowlpox) forming a third distinct basal cluster. Pox
isolates from one of these two clusters appear closely related to canarypox and other passerine pox viruses, while the second
appears more specific to Hawai‘i. There was no evidence that birds were infected simultaneously with multiple pox virus variants
based on evaluation of multiples clones from four individuals. No obvious temporal or geographic associations were observed
and strict host specificity was not apparent among the 4b-defined field isolates. We amplified a 116 bp 4b core protein gene
fragment from an ‘Elepaio (Chasiempis sandwichensis) collected in 1900 on Hawai‘i Island that clustered closely with the second of the two variants, suggesting that this variant
has been in Hawai‘i for at least 100 years. The high variation detected between the three 4b clusters provides evidence for
multiple, likely independent introductions, and does not support the hypothesis of infection of native species through introduction
of infected fowl. Preliminary experimental infections in native Hawai‘i ‘Amakihi (Hemignathus virens) suggest that the 4b-defined variants may be biologically distinct, with one variant appearing more virulent. These pox viruses
may interact with avian malaria (Plasmodium relictum), another introduced pathogen in Hawaiian forest bird populations, through modulation of host immune responses. 相似文献
18.
Askeyev OV Sparks TH Askeyev IV Tryjanowski P 《International journal of biometeorology》2007,51(6):459-463
We analysed data on the arrival dates of four species of leaf warbler (genus Phylloscopus) collected in Tatarstan between 1957 and 2004. There was no evidence over the whole period that the warblers returned to
their breeding sites significantly earlier, mainly because local temperatures for April and May, months when the majority
of birds arrived from their wintering grounds, did not increase significantly. However, arrival dates of two species (Chiffchaff
P. collybita and Willow warbler P.trochilus) were strongly related to local temperature in April, and that of Greenish warbler P. trochiloides to that in May. As expected, arrival dates for the three species wintering in Africa (Chiffchaff, Willow and Wood warblers
P. sibilatrix) correlated positively with one another (P < 0.01 in all cases), but were not correlated with arrival dates of Greenish warbler (P > 0.5 in all cases), a species wintering in the Indian sub-continent. 相似文献
19.
Males (n=34) and females (n=23) of long-tailed duck (Clangula hyemalis) collected on the southern coast of the Baltic Sea in winter were studied to determine brain tissue concentration of iron
(Fe), zinc (Zn), copper (Cu), manganese (Mn), and cadmium (Cd). There were no significant differences in the concentration
of metals between males and females, except for Cd, the concentration of which in male brains was twice that of the females.
In the brains of 20 birds (41% male and 26% female), the lead (Pb) concentration exceeded 1 μg/g wet wt. In all the duck brains
examined, Spearman correlation coefficients were significant and positive for Zn−Mn, Cu−Mn, Cu−Fe, and Pb−Fe; a negative correlation
was found for Pb−Zn. Additionally, female brains showed a positive correlation between Pb and Fe. The results obtained were
compared with literature data for diving and nondiving anseriforms and birds of other taxa. It seems that concentration of
heavy metals in the brain tissue of birds reflect natural adaptations (e.g., for diving) as well as effects of environmental
pollution. 相似文献
20.
Migrating Birds as Dispersal Vehicles for West Nile Virus 总被引:1,自引:0,他引:1
Jennifer Owen Frank Moore Nicholas Panella Eric Edwards Rachel Bru Megan Hughes Nicholas Komar 《EcoHealth》2006,3(2):79-85
Whereas migrating birds have been implicated in the spread of West Nile virus (WNV), there is no direct evidence of birds actively migrating while infectious. The role of birds in WNV dispersal is difficult to assess in the field. However, this role can be evaluated experimentally because birds in migratory disposition display increased locomotor activity or restlessness under captive conditions. We tested the following hypotheses: (1) migrating passerine birds continue to exhibit migratory activity while infectious with WNV and (2) the migratory state of the individual affects the magnitude of viremia. We examined the migratory activity of two neoarctic-neotropical passerine migrants, Swainson’s thrush (Catharus ustulatus) and gray catbird (Dumetella carolinensis), during acute WNV infection. All gray catbirds and six of nine Swainson’s thrushes exhibited migratory activity while infectious. Moreover, migratory status did not appear to influence viremia titers, as might be expected if individuals were immunosuppressed during migration. Therefore, we demonstrate that migrating passerine birds are potential dispersal vehicles for WNV. 相似文献