Short-eared Owl Asio flammeus (Pontoppidan, 1763) |
birds |
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Threats
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| The most significant threat to short-eared owls is habitat loss due to development, reforestation, wetland loss, and changes in farming practices such as conversion of hayfields to row crops or more frequent mowing of hayfields (Post 2004). As a ground-nesting bird, eggs and unfledged young are at risk of depredation by mammalian predators such as foxes, raccoons, and skunks. There is also increased risk of depredation by domestic and feral cats and dogs in areas with some development. A limiting factor for short-eared owls is their dependency on microtine rodent populations. Poisoning may be a threat in areas where humans are attempting to control rodent populations. As with many raptors, short-eared owls have been subjected to shooting by humans. |
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Management Considerations
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| Large areas of open habitat in breeding and wintering areas need to be maintained in order to ensure the persistence of this species in New York. Potential management practices include burning, mowing, and plowing of fields after the breeding season. Use Landowner Incentive Program funds to conserve privately-owned grasslands. Coordinate conservation efforts with other agencies and organizations and initiate an outreach program (Post 2004). |
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Research Needs
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| Population monitoring standards need to be developed and implemented to better estimate the local population status (distribution, abundance, and trends) during the breeding and non-breeding seasons. Current methods, such as flushing sitting females or roadside counts, are either labor and time intensive or result in under-estimating population sizes. More could be learned about nocturnal movements, migration patterns, adult and juvenile mortality, and the relationship between rodent abundance and territory size. Studies are needed on the effects of habitat management (i.e. burning, mowing, and plowing) on grassland birds (Post 2004) as well as small mammal populations. |
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Short-term Trends
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| Currently, it appears that populations are continuing to decline, although it may be difficult to determine trends due to the lack of precise location data from historical records (Schneider 2003). During the first Breeding Bird Atlas (1980-1985), there were five confirmed breeding records, nine probable breeding records, and 22 possible breeding records (Andrle and Carroll 1988). Data from the second Breeding Bird Atlas seems to indicate a decline with four blocks with confirmed breeding, nine blocks with probable breeding, and 11 blocks with possible breeding (McGowan and Corwin 2008). During the first Atlas, Short-eared Owls were recorded in nine blocks on Long Island, compared to one block during the second Atlas. Breeding may no longer occur in the lower Hudson Valley as well as a number of other historically known breeding sites in the state. Some records may be a single breeding event in an area with unusually high rodent populations. Overall, the distribution in New York is largely unchanged except for the reduction of reports on Long Island. Breeding Bird Survey data is too sparse in New York to determine trends. Wintering populations are variable depending on snow cover and rodent populations. It is difficult to determine winter population trends as few sites are surveyed on a regular basis. |
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Long-term Trends
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| During the early 20th century, Eaton (1914) reported short-eared owls as one of our most common owls outnumbering all other owls found in lowlands and marshes, especially in the winter. Approximately 60 years later, Bull (1974) described short-eared owl populations as declining with localized breeding reported. |
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