共查询到8条相似文献,搜索用时 0 毫秒
1.
Yukiko Inoue Ken Yoda Hidenori Fujii Hirofumi Kuroki Yasuaki Niizuma 《Journal of Ethology》2010,28(2):221-230
Infanticide, the killing of young animals by conspecifics, has been observed in diverse taxa. The function of infanticide
has been classified as exploitation, sexual selection, parental manipulation or resource competition. We observed infanticidal
behavior and its reproductive results at five breeding colonies of great cormorants from January to August 2008. Eighteen
cases of nest intrusions and/or attacks toward a chick by conspecific non-nest-owners were observed, and two of them were
filmed. In both attacks, perpetrators pecked the necks of chicks several times with display. The chicks bent their necks down
onto the nest and remained stationary. Our data did not support the exploitation hypothesis because adult cormorants did not
use chicks as food. In addition, the perpetrators were not true parents and did not mate with the female nest owner, indicating
that parental manipulation and sexual selection hypotheses were unlikely explanations. On the other hand, concurrent presence
of adults during prelaying and chick-rearing periods at a particular colony affected the occurrence of nest takeovers and
intrusions and/or attacks, suggesting that some conflicts over nests arise between individuals that are at different stages
of the breeding cycle. Digital videos relating to this article are available at and . 相似文献
2.
《Comparative biochemistry and physiology. C: Comparative pharmacology》1990,95(1):161-171
1. The concentration of individual PCBs was measured in adipose tissue of male and female puffins, shags, guillemots and cormorants obtained from the Isle of May and the Saltees islands.2. The concentrations of total PCBs showed positive correlations with that ofp,p'-DDE in the tissues.3. Enrichment factors were calculated by comparing the concentration of an individual PCB in the tissue with its abundance in commercial mixtures of PCBs.4. Of the 47 individual PCBs identified five prominent PCBs had enrichment factors considerably > 1 and accounted for approximately 35% of the total concentration of PCBs present. They shared the common molecular feature of chlorine atoms at adjacent meta-para positions in at least one of the biphenyl rings.5. Many PCBs had enrichment factors of <1, which suggested that they had been subjected to metabolism and presumably excretion. They shared the common feature of the absence of chlorine atoms at the meta-para positions of the biphenyl rings.6. These results support strongly the structural “rules” suggested in the preceding paper (Borlakoglu et al., 1990a) for the tendency of individual PCBs to accumulate or to be subjected to metabolism. 相似文献
3.
Merkel J Jones HI Whiteman NK Gottdenker N Vargas H Travis EK Miller RE Parker PG 《The Journal of parasitology》2007,93(3):495-503
Galapagos penguins (Spheniscus mendiculus) and flightless cormorants (Phalacrocorax harrisi) live in small, isolated populations on the westernmost islands of Isabela and Fernandina in the Galápagos Islands, Ecuador. Between August 2003 and February 2005, 4 field trips, 2 in the cool, dry season (August 2003 and August 2004) and 2 in the hot, rainy season (March 2004 and February 2005), were undertaken; 298 Galápagos penguins and 380 cormorants were sampled for prevalence and intensity of hemoparasites. Microfilariae were found in both the penguins and the cormorants. Blood smears were negative for the presence of other species of hemoparasites. Overall prevalence of microfilariae across seasons was 42.0% in cormorants and 13.8% in the penguins. Intensity of infection was generally low (mean = 3.2-31.7 in 25 fields across seasons and species) with the exception of a few individuals with markedly high intensities of parasites (>300 in 25 fields in 1 cormorant). Prevalence of microfilariae increased significantly over the 4 sampling periods for cormorants, but not for penguins. Prevalences were significantly higher in cormorants than in penguins for 3 of the 4 collecting trips. Male penguins had higher prevalences than females; however, there were no gender differences in cormorants. No relation was detected between body mass and either presence or intensity of parasitism. Morphological characteristics of the microfilariae are also described and specimens from each host species were similar in all characters measured. DNA sequence data from the mitochondrial cytochrome c oxidase subunit I gene were consistent with the morphological evidence and together demonstrate that the penguins and cormorants are likely to be infected with the same species of microfilariae. 相似文献
4.
In the Midi-Pyrénées region (southwest France), the increasing number of gravel pits has allowed the wintering of numerous species of waterbirds such as Great Cormorants (Phalacrocorax carbo). The debate about cormorant predation on fish stock has been sufficiently strong to have resulted in reductions in cormorant numbers by control shooting. In this context, cormorants were studied during winters 1996/1997 and 1997/1998 at two gravel pit sites in the Garonne floodplain. Human disturbances and fish densities were found to be the main parameters determining the abundance of fishing cormorants. This work will help to prompt further research and the development of a management strategy for this species. 相似文献
5.
Maki Yamamoto Akiko Kato Yan Ropert-Coudert Masayoshi Kuwahara Shinichi Hayama Yasuhiko Naito 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》2009,195(4):365-373
The characteristics of autonomic nervous activity were examined on captive great cormorants Phalacrocorax carbo hanedae, using a power spectral analysis of heart rate variability. Heart rates were calculated from recordings of the electrocardiograms
of the birds via embarked data loggers. We investigated the effects of blockades of the sympathetic or parasympathetic nervous
systems using the indices of autonomic nervous activity such as high frequency (0.061–1.5 Hz) component, low frequency (0.02–0.060 Hz)
component and the low frequency power component to high frequency power component ratio. Resting heart rate (85.5 ± 6.1 bpm)
was lower than the intrinsic heart rate (259.2 ± 15.3 bpm). The heart rate drastically increased after the injection of the
parasympathetic nervous blocker, on the other hand it slightly decreased after the injection of the sympathetic nervous blocker.
The sympathetic, parasympathetic and net autonomic nervous tones calculated from heart rate with and without blockades were
40.9 ± 27.6, −44.5 ± 7.4 and −29.5 ± 9.0%, respectively. The effect of the parasympathetic nervous blockade on low frequency
and high frequency power was greater than that of the sympathetic nervous blockade. Those data suggested that the parasympathetic
nervous activity was dominant for great cormorants. 相似文献
6.
Vieite Beatriz Braga Heitor O. Costa Neto Eraldo M. Azeiteiro Ulisses M. 《Aquatic Ecology》2022,56(3):667-684
Aquatic Ecology - Considerate the attitudes of traditional communities and their local ecological knowledge (LEK) can contribute to better policymaking and more appropriate management plans. Thus,... 相似文献
7.
Between January 1993 and January 1995, the number of Great Cormorants (Phalacrocorax carbo) using Lake Naivasha, Kenya (00° 45 S, 36° 20 E) for foraging and resting increased 56%, while the number of sympatric Long-tailed Cormorants (Phalacrocorax africanus) decreased 64%. In 1995 and 1996, we documented habitat changes and conducted monthly population and resource-use surveys of the two species in an attempt to discover the most likely reasons for these changes. The increase in Great Cormorants was probably the result of immigration from nearby Lake Nakuru due to extreme water level reductions there. Lake Naivasha also experienced falling water levels and transparency during this period, but these changes were not as severe and are not considered likely reasons for the decline in Long-tailed Cormorant numbers. Despite some probable dietary overlap, the two species were well separated in terms of foraging locations, foraging methods, resting habitats and breeding timing. The decline in Long-tailed Cormorant numbers may be connected with increased disturbance by fishermen along the lake littoral, this species' primary feeding location. 相似文献
8.
Moe B Brunvoll S Mork D Brobakk TE Bech C 《Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology》2005,175(1):21-30
Nestlings seem to face a trade-off between reducing the basal level of energy metabolism, as an energy-saving response, and maintaining thermogenic capacity during temporal food shortage. In the present study we examined developmental responses to short-term diet restriction of 12–16 day old nestling European shags kept under laboratory conditions and tested whether temporal food shortage delay the development of homeothermy. During food shortage the European shag nestlings substantially reduced basal level of energy metabolism, resulting in significant energy savings. The reduction in basal level of energy metabolism corresponded with a reduction in peak metabolic rate. At the same time, the low peak metabolic rate of diet-restricted nestlings was offset by a lower mass-specific minimal thermal conductance, and an increased mass-specific absolute scope. Consequently, the insulation and the portion of peak metabolic rate available for regulatory thermogenesis seemed to develop normally, as expected from age, during the period of food shortage. Further, the degree of homeothermy, measured as the index of homeothermy, was not significantly lower in diet-restricted nestlings compared to controls at the same age. We conclude that temporal food shortage did not significantly delay the development of homeothermy in the European shag nestlings despite substantial reductions in basal level of energy metabolism and peak metabolic rate.Communicated by: G. Heldmaier 相似文献