The Kestrel Project

Kestrel nest boxes were initially erected in southeastern Massachusetts in 1989 around cranberry bogs by Mike Maurer and Joey Mason. The town locations include Hanson, Lakeville, Marion, Middleboro, Plympton and Rochester, but the majority of boxes are in Carver and Wareham. The nest box used was designed by Joe Papp from Drummond, Wisconsin; designed for easy access for banding and having a slide out bottom that can be removed to discourage squirrel inhabitants. Mason has continued to maintain and monitor up to 38 nest boxes from this previous study since 2000, when Keeping Company with Kestrels was established.

Nest boxes used to be 75% occupied in the mid 1990’s, but KCK’s boxes were only 34% occupied in 2006 and 2007. This is a serious decline and concern. In 2014 we had 44.4% with 3 failed due to abandoned eggs. This year (2015) we had 45.7% occupancy and only one failed . It appears that maybe Kestrel occupancy is at least maintaining for the time being.

Since much of Massachusetts’ open space grassland has been or is being developed, this leaves cranberry bogs as one of the last few Kestrel sustaining habitats in this area. For the last 10 years fewer adult Kestrels have been returning in the spring to nest and their overall numbers have noticeably dropped. There is speculation that the increase in Cooper’s Hawks is to blame, but other contributing factors may be at play, such as housing developments and loss of open grassland habitat needed to forage for food during spring and fall migration. West Nile Virus has killed raptors, but was statistically ruled out as the cause of the decline. Weather can also impact these small raptors. There is documentation for all these issues, but is the decline due to one critical aspect or a combination of all?

During the nesting season the Kestrel young are banded with aluminum U.S. Fish and Wildlife Service bands, allowing us to age them when recaptured in succeeding years. The oldest recaptures have lived at least 6 years of age. Some of our banded Kestrels have traveled as far south as Boca Raton, Florida. This 2013 season an additional green alpha/numeric band will be applied in hopes of being able to read individual codes from a distance.

Images may not be reproduced without the permission of the photographers.
Images by Joey Mason © 2011 and Jeremy Kezer © 2011.