During the winter of 2009 grassland birds were monitored in the region of Cuchillas de la Zarca to estimate the association betweenAmmodramus bairdiiAudubon 1844, focal species of grassland and bird species belonging ...During the winter of 2009 grassland birds were monitored in the region of Cuchillas de la Zarca to estimate the association betweenAmmodramus bairdiiAudubon 1844, focal species of grassland and bird species belonging to the trophic guild of grassland granivorous birds (n = 25 ). The study area was divided into monitoring quadrants (n = 16) where 96 transects for bird monitoring were conducted, recording 16,635 individuals of which only 32.9% were in the trophic guild of grassland granivorous birds. The association betweenA. bairdiiand other species was estimated from the nonparametric statistical index of Kendall’s coefficient of concordance (W) and the p value, through permutation analysis (n = 10,000), finding positive and significant associations (p≤0.05) of the target species for study withSturnella magna,Passerculus sandwichensisandAmmodramus savannarum, species that share habitat preferences of natural grassland in good condition, slightly grazed and with little tolerance to the shrub cover. The association W ranged from 0.072 and 0.749. These results can recognize this region as an important area for the conservation of obligate grassland birds during winter, suggesting establish training programs to better utilize this resource by means of cattle activity.展开更多
Grassland bird populations have declined more than any other group of bird species in North America. Some species such as the grasshopper (Ammodramus savannarum) and Baird’s sparrows (Ammodramus bairdii) are of parti...Grassland bird populations have declined more than any other group of bird species in North America. Some species such as the grasshopper (Ammodramus savannarum) and Baird’s sparrows (Ammodramus bairdii) are of particular conservation concern, since they have shown negative trends in their population over the last 50 years. Their winter ecology has only begun to be studied recently and information is limited. The purpose of this study is to achieve the morphometric characterization of these two grassland species during the wintering season. The study is conducted in the Rancho Santa Teresa located in Villa Hidalgo, Durango, Mexico and the Ecological reserve “El Uno”, located in Janos, Chihuahua, Mexico. During winter 2013-2014, 135 birds were captured;banded and zoometric measurements were taken such as total body weight, wing chord, tail length, culmen, and beak depth and width. Two indices of body condition (BCI) are also calculated. All measurements and indices are compared per species and per sex. Both species are sexed with molecular techniques, determining 20 females and 18 males for A. bairdii and 41 females and 56 males for A. savannarum. All variables are significant different between species (p < 0.05). Beak measurements are not significantly different when comparing birds of different sexes (same species), with the exception of beak width of A. bairdii (p < 0.05). Male’s weight, wing chord, tail length, as well as one of the body condition indices (BCI2) are significantly higher (p < 0.05) than females’ for both species. BCI1 shows significant differences (p < 0.05) between species and sexes in A. bairdii. The biometric data obtained in this study can be used as reference values wintering populations of both species.展开更多
The Baird’s tapir(Tapirus bairdii)is a popular game species throughout Central America,particularly among in-digenous populations,and is currently endangered.Research on Miskitu hunting was conducted over 4 months in...The Baird’s tapir(Tapirus bairdii)is a popular game species throughout Central America,particularly among in-digenous populations,and is currently endangered.Research on Miskitu hunting was conducted over 4 months in a remote region in northeastern Honduras that overlaps with the Río Plátano Biosphere Reserve.The hunting zone was mapped together with hunters and interviews were conducted with elders and other community mem-bers about tapir hunting.Results show that tapir harvesting is targeted toward specific habitats at specific times of year.Harvest rates for one year suggest that tapir hunting in the area exceeds estimates of maximum sustain-able production.Nevertheless,field surveys reveal the presence of tapir within 1 km of the community,and its harvest tends to be nearby,in both forested and agricultural landscapes,suggesting that the animal has not been depleted in the area.It appears that the existence of forest areas adjacent to the hunting zone that do not experi-ence hunting,together with the anthropogenic habitats created through shifting cultivation,are factors that help explain the presence of tapirs in the area.The article concludes with a discussion regarding the potential posi-tive role of indigenous hunters in tapir conservation throughout its distribution range.展开更多
文摘During the winter of 2009 grassland birds were monitored in the region of Cuchillas de la Zarca to estimate the association betweenAmmodramus bairdiiAudubon 1844, focal species of grassland and bird species belonging to the trophic guild of grassland granivorous birds (n = 25 ). The study area was divided into monitoring quadrants (n = 16) where 96 transects for bird monitoring were conducted, recording 16,635 individuals of which only 32.9% were in the trophic guild of grassland granivorous birds. The association betweenA. bairdiiand other species was estimated from the nonparametric statistical index of Kendall’s coefficient of concordance (W) and the p value, through permutation analysis (n = 10,000), finding positive and significant associations (p≤0.05) of the target species for study withSturnella magna,Passerculus sandwichensisandAmmodramus savannarum, species that share habitat preferences of natural grassland in good condition, slightly grazed and with little tolerance to the shrub cover. The association W ranged from 0.072 and 0.749. These results can recognize this region as an important area for the conservation of obligate grassland birds during winter, suggesting establish training programs to better utilize this resource by means of cattle activity.
文摘Grassland bird populations have declined more than any other group of bird species in North America. Some species such as the grasshopper (Ammodramus savannarum) and Baird’s sparrows (Ammodramus bairdii) are of particular conservation concern, since they have shown negative trends in their population over the last 50 years. Their winter ecology has only begun to be studied recently and information is limited. The purpose of this study is to achieve the morphometric characterization of these two grassland species during the wintering season. The study is conducted in the Rancho Santa Teresa located in Villa Hidalgo, Durango, Mexico and the Ecological reserve “El Uno”, located in Janos, Chihuahua, Mexico. During winter 2013-2014, 135 birds were captured;banded and zoometric measurements were taken such as total body weight, wing chord, tail length, culmen, and beak depth and width. Two indices of body condition (BCI) are also calculated. All measurements and indices are compared per species and per sex. Both species are sexed with molecular techniques, determining 20 females and 18 males for A. bairdii and 41 females and 56 males for A. savannarum. All variables are significant different between species (p < 0.05). Beak measurements are not significantly different when comparing birds of different sexes (same species), with the exception of beak width of A. bairdii (p < 0.05). Male’s weight, wing chord, tail length, as well as one of the body condition indices (BCI2) are significantly higher (p < 0.05) than females’ for both species. BCI1 shows significant differences (p < 0.05) between species and sexes in A. bairdii. The biometric data obtained in this study can be used as reference values wintering populations of both species.
文摘The Baird’s tapir(Tapirus bairdii)is a popular game species throughout Central America,particularly among in-digenous populations,and is currently endangered.Research on Miskitu hunting was conducted over 4 months in a remote region in northeastern Honduras that overlaps with the Río Plátano Biosphere Reserve.The hunting zone was mapped together with hunters and interviews were conducted with elders and other community mem-bers about tapir hunting.Results show that tapir harvesting is targeted toward specific habitats at specific times of year.Harvest rates for one year suggest that tapir hunting in the area exceeds estimates of maximum sustain-able production.Nevertheless,field surveys reveal the presence of tapir within 1 km of the community,and its harvest tends to be nearby,in both forested and agricultural landscapes,suggesting that the animal has not been depleted in the area.It appears that the existence of forest areas adjacent to the hunting zone that do not experi-ence hunting,together with the anthropogenic habitats created through shifting cultivation,are factors that help explain the presence of tapirs in the area.The article concludes with a discussion regarding the potential posi-tive role of indigenous hunters in tapir conservation throughout its distribution range.
