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The ovenbird, one of the most common forest bird species on Camp Ripley, and a species in
greatest conservation need, has shown an increasing trend since 2000. In fact, the average number of
ovenbirds per plot and total number of ovenbirds counted had more than doubled by 2007 and
increased substantially again in 2009 (Figure 22). The Breeding Bird Survey trend for ovenbirds has
been increasing in the state, within the Great Lakes Transition physiographic region (in which Camp
Ripley is located), regional, and national levels since 2000 (Sauer et al. 2008), but not to the same
extent as on Camp Ripley.
Ovenbirds have the capability to use a number of different plant communities for breeding.
However, certain vegetative structural characteristics of ovenbird territories have been identified.
Vegetation features from ovenbird territories show a more closed canopy, larger trees, less ground
cover, and smaller conifer basal area than adjacent areas of unoccupied forest. Of primary importance
for breeding is a large area of contiguous, interior forested habitat (Van Horn and Donovan 1994).
Except for ground cover, these are similar requirements for red-eyed vireos. Red-eyed vireos are
usually absent from sites where understory shrubs are sparse or lacking. Both species are more
abundant in forest interior than near edges, which indicates they are susceptible to forest
fragmentation.
Average Birds per Plot
2.50
2.00
1.50
1.00
0.50
0.00
*In 2001 and 2002 only 31 and 30 plots were surveyed respectively.
In the past, red-eyed vireos were much more numerous than any other species detected on
survey plots. However, the number of red-eyed vireos per plot and the total number on all plots have
declined by more than 70 percent since 2000 (Figure 23). This decrease is not known to occur in other
surveys in the state, region and country.
2009 Conservation Program Report
2000
Figure 22. Camp Ripley selected songbirds of greatest
conservation need, 2000 to 2009.
2001
2002
2003
2004
2005
2006
Page 36
2007
2008
2009
Ovenbird
(Seiurus aurocapillus)
Veery
(Catharus fuscescens)
Least Flycatcher
(Empidonax minimus)
Eastern Wood-pewee
(Contopus virens)