The Wilson Journal of Ornithology 123( 1 ):59—64, 2011 
WINTERING BIRD RESPONSE TO FALL MOWING OF 
HERBACEOUS BUFFERS 
PETER J. BLANK. 1 - 3 ' 5 JARED R. PARKS, 2 - 4 AND GALEN P. LIVELY 2 
ABSTRACT.—Herbaceous buffers are strips of herbaceous vegetation planted between working agricultural land and 
streams or wetlands. Mowing is a common maintenance practice to control woody plants and noxious weeds in herbaceous 
buffers. Buffers enrolled in Maryland’s Conservation Reserve Enhancement Program (CREP) cannot be mowed during the 
primary bird nesting season between 15 April and 15 August. Most mowing of buffers in Maryland occurs in late summer 
or fall, leaving the vegetation short until the following spring. We studied the response of wintering birds to fall mowing ot 
buffers. We mowed one section to 10-15 cm in 13 buffers and kept another section unmowed. Ninety-two percent of birds 
detected in buffers were grassland or scrub-shrub species, and 98% of all birds detected were in unmowed buffers. Total 
bird abundance, species richness, and total avian conservation value were significantly greater in unmowed buffers, and 
Savannah Sparrows (Passerculus sandwichensis), Song Sparrows (Melospiza melodia), and White-throated Sparrows 
(Zonotrichia albicollis ) were significantly more abundant in unmowed buffers. Wintering bird use of mowed buffers was 
less than in unmowed buffers. Leaving herbaceous buffers unmowed through winter will likely provide better habitat for 
wintering birds. Received 21 December 2009. Accepted 23 August 2010. 
Herbaceous buffers are strips of herbaceous 
vegetation planted between working agricultural 
land and streams or wetlands. They are designed 
to manage environmental concerns such as water 
quality and can provide habitat for a variety of 
wildlife species (Clark and Reeder 2005). The 
U.S. Department of Agriculture's (USDA) Con¬ 
servation Reserve Program (CRP) offers several 
types of herbaceous buffer practices to agricul¬ 
tural producers, and Maryland’s Conservation 
Reserve Enhancement Program (CREP) offers 
additional financial incentives for landowner 
enrollment. Over 15,000 ha of herbaceous buffers 
are established in Maryland through the CRP 
(USDA 2010), most of which are enrolled in 
Maryland’s CREP. Herbaceous buffers in Mary¬ 
land are usually planted either to native warm- 
season grasses or cool-season grasses with the 
addition of native wildflowers or introduced 
legumes (USDA 2009b). 
Maintenance is required to keep CREP plant¬ 
ings in Maryland in good condition and function¬ 
ing properly (USDA 2009b). Mowing is a 
common maintenance practice to control woody 
1 Marine-Estuarine-Environmental Sciences Program, 
University of Maryland, College Park, MD 20742, USA. 
-Department of Entomology, University of Maryland, 
College Park, MD 20742, USA. 
'Current address: USGS, Patuxent Wildlife Research 
Center, 12100 Beech Forest Road, Laurel, MD 20708, 
USA. 
4 Current address: Eastern Shore Land Conservancy 
Southern Office, 601 Locust Street, Suite 302, Cambridge, 
MD 21613, USA. 
'’Corresponding author; e-mail: blankpj@gmail.com 
plants and noxious weeds in herbaceous plantings. 
Mowing is generally not allowed on CRP or 
CREP land during the primary nesting and brood 
rearing seasons for wildlife (dates vary from state 
to state), but is allowed during the rest of the year. 
Maryland’s CREP land may not be mowed 
between 15 April and 15 August (USDA 
2009b). Most mowing of buffers in Maryland 
occurs in late summer or fall (hereafter, fall 
mowing) and often within a few days of 15 
August (P. V. Barry, pers. comm.; J. E. Gerber, 
pers. comm.). Fall mowing is also a common 
practice in herbaceous CRP plantings in other 
states, including Virginia (G. I. Hall, pers. 
comm.), Ohio (M. D. DeBrock, pers. comm.), 
and Tennessee (M. E. Zeman, pers. comm.). Fall 
mowing leaves the vegetation short until growth 
begins the following spring. Farm managers often 
choose to mow in fall instead of late winter or 
spring because they believe shorter grass looks 
better, the ground may be too wet in spring for 
mowing, or fall is when they have the most time 
available (S. V. Strano, pers. comm.). 
It is recommended that buffers be mowed no 
more than once every 2 to 3 years with no more 
than half of the area mowed in any 1 year (USDA 
2009b). A common recommendation is to mow a 
third of each buffer every year on a 3-year rotation 
(USDA 2009b). However, some farm managers 
mow entire buffers each year (PJB, pers. obs.). 
Buffers often represent the only uncultivated 
herbaceous areas on farmland in Maryland and 
may be important habitat for early-successional 
birds. Many studies have evaluated the response 
by breeding birds to mowing of early-successional 
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