Columbia River Streaked Horned Lark Surveys and Monitoring

The Center for Natural Lands Management (CNLM) has been monitoring streaked horned larks and their ecology on deposition placement sites in the lower Columbia River since 2010. Although periodic placement of dredged materials provide suitable habitat for larks, deposition islands appear to be suitable for a limited period, apparently between 2 to 3 and 7 to 8 years after creation (Anderson 2013). Understanding where larks occur and their abundance is key to minimizing impacts from deposition actions as well as maximizing the habitat creation benefits of dredged material placement. By monitoring lark distribution and population trends through time, we can also improve our knowledge of how larks are respond to deposition actions.

Our goal was to acquire and provide to the US Army Corps of Engineers (USACE) information regarding SHLA occupancy, distribution, and habitat use in 2015 at 23 dredged material deposition sites in the USACE disposal network.

Our objectives were to:
1) Assess lark occupancy at sites previously not surveyed or where larks were previously undetected but suitable habitat occurs.
2) Estimate abundance and assess trends at known occupied sites.
3) Conduct SHLA territory mapping.
4) Make recommendations for future monitoring.