نتایج جستجو برای: captive breeding and re

تعداد نتایج: 16860702  

Journal: :Journal of Animal Behaviour and Biometeorology 2023

The red panda (Ailurus fulgens) population is decreasing, with less than 10,000 individuals in the wild because of habitat destruction, fragmentation, and illegal hunting. Captive breeding has become an increasingly crucial strategy for conserving endangered species, but efforts to generate self-sustaining populations have failed despite ample resources being allocated. Animals are often stress...

Journal: :Reproduction, fertility, and development 2016
C Ververs M Hostens M van Zijll Langhout M Otto J Govaere A Van Soom

During the last decade, the population of wild white rhinoceroses has been in steady decline, mainly because of increased poaching incidents and habitat loss. Therefore, more data are necessary on reproduction of this endangered species in order to improve captive breeding, which is at present not very successful. Currently, ~20,000 Southern white rhinoceroses are remaining of which the majorit...

Journal: :Hormones and behavior 1991
E D Ketterson V Nolan L Wolf C Ziegenfus A M Dufty G F Ball T S Johnsen

To assess whether alterations in the normal pattern of testosterone (T) secretion might be beneficial or detrimental, we studied a breeding population of dark-eyed juncos in which we elevated T experimentally and measured its effect on potential correlates of fitness. We treated both free-living and captive males with implants that were either empty (C-males, controls) or packed with T (T-males...

Journal: :ILAR journal 2007
Robert K Browne Kevin Zippel

Reproduction technologies for amphibians are increasingly used for the in vitro treatment of ovulation, spermiation, oocytes, eggs, sperm, and larvae. Recent advances in these reproduction technologies have been driven by (1) difficulties with achieving reliable reproduction of threatened species in captive breeding programs, (2) the need for the efficient reproduction of laboratory model speci...

2011
J. M. Cornelius

Along with many current studies investigating the impact of climatic change on the behavioural patterns of migratory birds, the paper by Studds & Mara [1] demonstrates relationships between environmental conditions and timing of departure from an overwintering site—Font Hill Nature Preserve in southwestern Jamaica—of the American Redstarts (Setophaga ruticilla), a Neotropical–Nearctic migrant. ...

2015
Tomasz Strzała Artur Kowalczyk Ewa Łukaszewicz Bi-Song Yue

The Western capercaillie (Tetrao urogallus) is a specific bird species, which, despite its very broad distribution and large global population size, is highly endangered in many Western and Central European countries. According to the species situation, in many countries (including Poland), breeding and reintroduction programmes have been started. One of the most complex and large-scale reintro...

Journal: :The American naturalist 2001
J M Casto V Nolan E D Ketterson

Monogamous and polygynous male songbirds generally differ in their breeding season profiles of circulating testosterone. Testosterone level spikes early in the breeding season of monogamists and then declines, but it remains high in polygynists. Male dark-eyed juncos (Junco hyemalis) are socially monogamous and exhibit the usual pattern, but experimental maintenance of high testosterone through...

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