Bank Swallow (Riparia riparia)

Photo by Jack BartholmaiBank Swallow by Jack BartholmaiBank Swallow distribution map

Status/Protection

Population Information

The Federal BBS information can be obtained at http://www.mbr-pwrc.usgs.gov/bbs/bbs.html by clicking on Trend Estimates and selecting the species in question. All estimates are for time period (1966-2005).

Life History

Habitat Selection

Bank Swallows breed primarily in lowland areas along ocean coasts, rivers, streams, lakes, reservoirs, and wetlands. They nest in colonies, sometimes containing >3,000 pairs (Garrison 1999). In Wisconsin, colonies of 3-500 pairs have been recorded (Robbins 1991). Bank Swallows excavate their own burrows along vertical cliffs, banks, and bluffs, as well as gravel pits and roadside banks exposed during highway construction (Garrision 1999). Burrows are dug parallel to the ground surface and range from 10-340 cm deep. Foraging habitat surrounding the colony includes agricultural areas, wetlands, grasslands, and open water (Garrison 1998).

Habitat Availability

This species is broadly distributed throughout Wisconsin but populations fluctuate depending on nest site availability (Damro 2006). Colony sites are ephemeral and largely dependent on erosion to maintain suitability. Flood control and bank stabilization activities often result in loss or alteration of suitable colony sites. However, road cuts, gravel and sand quarries, or other activities that create vertical banks in friable soils can benefit this species, assuming disturbance is minimized during the nesting period (Garrison 1999).

Population Concerns

Breeding Bird Survey data suggest a non-significant decline range-wide and a non-significant increase in Wisconsin (Sauer et al. 2005). However, accurate population estimates are difficult because of this species’ localized distribution and erratic occupancy of colony sites (Garrision 1999). In Wisconsin it is considered a common to fairly common summer resident throughout the state (Robbins 1991). During the Wisconsin Breeding Bird Atlas (1995-2000), observers confirmed breeding in approximately 25% of the surveyed quads (Damro 2006).

The direct loss of suitable colony sites through flood control and bank stabilization projects is a significant threat (Garrison 1998). Little is known regarding threats on the wintering ground.

Recommended Management

Because of the ephemeral nature of nest colonies, it is difficult to concentrate management efforts in any one location. Therefore, all areas with current or potential colony sites should be identified and conserved in Wisconsin. Wherever possible, managers should consider maintaining natural cycles (i.e., flooding and erosion) in riparian ecosystems, which will benefit many riparian-associated species. However, public education on the importance of these natural processes is needed. Artificial habitat enhancement efforts (i.e., bank and burrow construction) proved marginally successful in California. Bank Swallows occupied artificial sites for three seasons, but later abandoned them due to overgrown vegetation and hard soils (Garrison 1999). Thus, long-term maintenance costs may preclude this from being a viable management strategy.

Research Needs

Most aspects of this species’ life history are well-studied on the breeding grounds. However, regional data are sometimes lacking. For instance, important breeding sites in Wisconsin need to be identified and studied. Furthermore, collecting nesting productivity data in conjunction with a habitat inventory at these sites would further state management efforts. Double brooding in this species needs clarification. More information is needed on habitat usage, distribution, and behavior during migration and winter in the Americas (Garrison 1999).

Information Sources

References

Contact Information

Kreitinger, K., Y. Steele and A. Paulios, editors. 2013.
The Wisconsin All-bird Conservation Plan, Version 2.0. Wisconsin Bird Conservation Initiative.
Wisconsin Department of Natural Resources. Madison, WI.

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