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Effigies for Dispersing Urban Crow Roosts

  • Author(s): Avery, Michael L.
  • Tillman, Eric A.
  • Humphrey, John S.
  • et al.
Abstract

The use of real and artificial effigies has proven to be an effective alternative to pyrotechnics and other traditional methods for the dispersal of nuisance vulture roosts. During the winters of 2005-2006 and 2006-2007, we applied the same principles of effigy use to a large urban crow roost in the Lancaster, PA area. The initial deployment of effigies occurred in November 2005 in a wooded area where approximately 10,000 birds had already congregated to the detriment of nearby businesses. By December, as the roost grew to approximately 40,000 birds, we successively moved the birds to a series of alternate sites along a wooded creek. In January, the crows split into smaller roosting aggregations and began to disperse. In October 2006, before wintering crows arrived, we installed effigies in wooded areas where the crows had settled the previous year. Although preferred roost habitat in 2005-2006, these areas were used only sparingly by crows throughout the second winter. Instead, crow roosting activity was focused in downtown Lancaster. At wooded sites where 5,000-10,000 birds did settle, we installed additional effigies and the birds responded by leaving. During November-December 2007, we provided technical assistance to a citizen-based crow management effort that successfully incorporated the use of artificial crow effigies with other harassment to move the roost (30,000 to 40,000 birds) to a site acceptable to the community. We conclude that crow effigies (carcasses, taxidermic mounts, or artificial models) are useful components of roost dispersal efforts and can possibly be used in other applications, such as crop damage management.

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