Saturday, February 5, 2011

Health

Pintail nests and chicks are vulnerable to predation by mammals, such as foxes and badgers, and birds like gulls, crows and magpies. The adults can take flight to escape terrestrial predators, but nesting females in particular may be surprised by large carnivores such as bobcats.[10] Large birds of prey, such as Northern Goshawks, will take ducks from the ground, and some falcons, including the Gyrfalcon, have the speed and power to catch flying birds.[18]

Male preeningIt is susceptible to a range of parasites including Cryptosporidium, Giardia, tapeworms, blood parasites and external feather lice,[19][20][21][22] and is also affected by other avian diseases. It is often the dominant species in major mortality events from avian botulism and avian cholera,[23] and can also contract avian influenza, the H5N1 strain of which is highly pathogenic and occasionally infects humans.[24]
The Northern Pintail is a popular species for game shooting because of its speed, agility, and excellent eating qualities, and is hunted across its range.[25][26] Although one of the world's most numerous ducks,[16] the combination of hunting with other factors has led to population declines, and local restrictions on hunting have been introduced at times to help conserve numbers.[27]
This species' preferred habitat of shallow water is naturally susceptible to problems such as drought or the encroachment of vegetation, but this duck’s habitat might be increasingly threatened by climate change.[16] Populations are also affected by the conversion of wetlands and grassland to arable crops, depriving the duck of feeding and nesting areas. Spring planting means that many nests of this early breeding duck are destroyed by farming activities,[28] and a Canadian study showed that more than half of the surveyed nests were destroyed by agricultural work such as ploughing and harrowing.[29]

FemaleHunting with lead shot, along with the use of lead sinkers in angling, has been identified as a major cause of lead poisoning in waterfowl, which often feed off the bottom of lakes and wetlands where the shot collects.[30] A Spanish study showed that Northern Pintail and Common Pochard were the species with the highest levels of lead shot ingestion, higher than in northern countries of the western Palearctic flyway, where lead shot has been banned.[31] In the United States, Canada, and many western European countries, all shot used for waterfowl must now be non-toxic, and therefore may not contain any lead.[32][33][34]

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