ARE SUl\FLOWER FIELDS FOR THE BIRDS?
HEATH M. HAGY , North Dakota State University , Department of Biological Sciences , Fargo , ND, USA GEORGE M. LINZ, USDA, APHIS , Wildlife Services, National Wildlife Research Center , Bismarck , ND, USA WILLIAM J. BLEIER , N011h Dakota State University , Department of Biological Sciences, Fargo , ND , USA
Abstract: The northern Great Plains are home to a variety of birds throughout the year, particularly during migration. Migratory species use native and restored grasslands, shelterbelts, and agricultural fields for food and shelter in North Dakota. Blackbirds (Xanthocephalus xanthocephalus) have been documented to cause economically important damage to some crops and thus , are sometimes the target of concerted harassment efforts. Few studies have assembled an inventory of non blackbirds using small grain fields during the fall and spring in North Dakota that may be inadvertently affected by blackbird management. At least 94 nonblackbird species use crop fields in the spring and fall in North Dakota. Sunflower fields appear to be a particularly important stopover habitat for a variety of migratory birds , with 78 species and 29 species using sunflower in the fall and spring, respectively . We encourage a joint blackbird management / wildlife habitat system including Wildlife Conservation Sunflower Plots (lure plots) as part of an integrated pest management plan to reduce blackbird damage to sunflower and provide habitat for nonblackbirds.
Key words: blackbirds , decoy plots , lure plots, nonblackbirds , stopover habitat , WCSP
Proceedings of the l ih Wildlife Damage Management Conference (D.L. Nolte , W.M. A1:jo, D.H. Stalman , Eds) . 2007
INTRODUCTION use crop fields and shelterbelts in the NGP. The northern Great Plains (hereafter These areas have become important habitats NGP) of North America provide stopover for some migratory species , especially as habitat for a wide variety of migratory birds. some North American birds have Forest species , grassland species , and habitat experienced population declines (Robbins et generalists migrate across a patchwork of al. 1989, Askins et al. 1990, Askins 1993, agriculture that fragments the once 1999 , 2000 , Murphy 2003) . continuous grasslands of the NGP into a Population and habitat selection mosaic of commercial grain crops , hay studies of farmland birds are heavily biased lands , grazing pastures , and shelterbelts. towards the breeding grounds , with little Presently , patches of Conservation Reserve information available about the wintering Program (CRP) grasslands, grazing pastures , ground habitat and even less regarding and wildlife-managed lands represent the stopover site selection. Though site selection majority of the prairie remnants within the is likely hierarchical , studies quantifying cultivated landscape of NGP. With reduced habitat variables in stopover locations are grassland habitats available, migratory birds lacking (Wiens 1973, Johnson 1980).
61 Peterjohn (2003) describes understanding of pho eniceus) , common grackles (Quiscafus the habitat requirements of many farmland quis cula), and yellow-headed blackbirds birds during non-breeding seasons as (Xantho cephalu s xantho cephalu s), con "rudimentary. " Quality stopover habitat is gregate in large mixed-species foraging vital for migrants , especially when they are flocks and may do substantial damage to bound for breeding grounds as lean birds commercial crops. The close proximity of may not be as attractive to females nor be commercial agriculture and abundant able to defend a territory until they feed and roosting habitat , cattail-emergent wetlands, increase their fat stores (Moore and Simons make this region attractive to blackbirds . As 1989) . Fat depleted birds must also remain No11h Dakota and South Dakota sunflower longer at stopover sites increasing the risk of production supports a regional economy predation . Stopover sites which provide worth over $906 million , significant crop cover and large amounts of accessible forage losses could reduce future sunflower spread over a large area may lead to reduced plantings and negatively affect rural stopover time. economies in the region (Bangsund and Many migratory bird species inhabit Leistritz 1995). the Prairie Pothole Region of the NGP, Many methods have been researched using small , isolated wetlands , prame and implemented in the last 50 years to patches , emergent wetland vegetation, and reduce blackbird damage to com and agricultural crops for food , nesting habitat , sunflower in the NGP (A very 2003 , and cover. Though the NGP is highly Cummings and A very 2003 , Linz et al. fragmented, grassland birds and other 2003) . Producers and researchers have tried species inhabit row-crop fields , roadsides , hazing birds with airplanes, frightening grass patches , and other areas (Best et al. devices, propane cannons, and firearms , and 1998, Herkert 1998, McCoy et al. 1999, have implemented roost habitat management Schaaf 2003 , Galle 2006 , Hagy 2006). Best with mixed success (Linz et al. 1992, 2003) . et al. ( 1998) found more wintering species in In the early 1980s, Cummings et al. ( 1987) row-crop fields than in CRP fields in six showed that ''decoy" plantings of sunflower Midwestern states . Martin ( 1980) observed might reduce bird damage to commercial n1ore than 65 avian species using sunflower fields , though strategic placement shelterb elts as stopover habitat during spring of the plots was critical for their success. migration in eastern South Dakota. Researchers have documented bird use of Shelterbelts provide forest islands that have agriculture in North Dakota comparing both contributed to the westward expansion of blackbird and nonblackbird use across some forest birds (Spnmt 1975, Johnson and common row-crops. [n this paper , we will Beck 1988) . Clearly , the NGP provide focus on three studies which examined a habitat for a large number of migratory variety of row-crops in central and eastern birds . North Dakota in order to demonstrate the Though crop fields may provide importance of agricultural habitat to adequate habitat for birds , not all of these migratory nonblackbirds , especially migrants are welcomed visitors , especially sunflower. by sunflower producers . An estimated 75 million blackbirds migrate through the NGP STUDY AREA in the fall to feed on waste grain and These studies were conducted within standing crops , the latter including corn and central and eastern North Dakota. Schaaf sunflower (Linz et al. 2003). Blackbirds, (2003) conducted observations in Barnes including red-winged blackbirds (Agelaius and Stutsman counties in the Southern Drift
62 Plains physiographic subregion. Galle were significant relationships between bird (2006) conducted observations across l 8 abundance and surrounding habitats. counties within the Southern Drift Plains of Hagy (2006) examined bird use east- central part of the state. Hagy (2006) throughout east- central North Dakota in 35 worked in the Southern Drift Plains, the locations , each site including 1 commercial Northern Drift Plains , and the Missouri sunflower field, One Wildlife Conservation Coteau subregions of east and central North Sunflower Plot (hereafter WCSP) , and one Dakota within a 14-county area. Although non-sunflower commercial agricultural row this area was once dominated by tall- and crop field ( corn , wheat , soybeans, field pea, mixed-grass prairies , it is now heavily canola, or flaxseed) in the fall of 2004 and cultivated (Barbour et al. 1999). Agriculture 2005. Additionally , his study examined is a valuable industry in North Dakota, as it habitat variables within and surrounding contributes to 25% of the state's economic each field type using model selection to base and over 8% of its gross state product elucidate relationships between avian (Leistritz et al. 2002). abundance and habitat variables. Sunflower is an important crop , both These authors used different ecologically and economically , in North methodologies , but all gathered valuable Dakota, as well over I billion pounds of information regarding avian use of crop sunflower seed is produced annually on 0.44 fields. Schaaf (2003) and Hagy (2006) million ha (USDA 2005) . In 2005, North conducted 50 m fixed radius circular point Dakota produced 45% of all oilseed , 39% of counts with supplemental mist-netting to all confectionary, and 42% of the total thoroughly evaluate species richness in sunflower grown in the United States sunflower (Reynolds et al. 1980, Poulin et (USDA 2005). al. 2000). They conducted 8 min point counts beginning shortly after sunrise until METHODS all fields were surveyed (~ 2-5 hr). Hagy rn fall of 2000 and 200 l, Schaaf (2006) and Schaaf (2003) used mist nets in (2003) identified and quantified WCSP and commercial sunflower fields , nonblackbirds in 12 ripening sunflower respectively . Hagy (2006) conducted point fields in Barnes and Stutsman counties, counts only in commercial sunflower and North Dakota. This study also measured non-sunflower crop fields . Galle (2006) used habitat parameters in and around the fields , a line-transect method to count birds, which in order to examine possible co1Telation is more efficient than other methods for between these factors and nonblackbird migration monitoring , especially 111 open abundance using Pearson product-moment habitats (Wilson et al. 2000). correlations . The aim of this study was to develop infom1ation to evaluate the RESULTS importance of sunflower as habitat for post Across studies , 94 species were breeding birds. documented (Schaaf 2003 , Galle 2006 , In the spring of 2003 and 2004 , Galle Hagy 2006) to use crop fields in the spring (2006) examined avian activity on 114 and fall in North Dakota (Table 1). Within sunflower , soybean, corn, and other small all crop fields , abundance , density, and grain fields throughout the Southern Drift species richness were highest in sunflower Plains of North Dakota. Additionally , (Galle 2006 , Hagy 2006). habitat variables surrounding study fields were quantified using GIS and principal component analysis to determine if there
63 Table 1. Bird species observed in North Dakota with associated crop type (S - sunflower or C - other crop) and migration period (S - spring or F - fall). AOU Code Common Name SQecies Name CroQ Migration Period AMCR American Crow Corvus brachyrhynchos s S,F AMGO American Goldfinch Carduelis tristis S, C F AMKE American Kestrel Falco sparverius s F AMPI American Pipit Anthus rubescens s F AMRO American Robin Turdus migratorius S,C S,F ATSP American Tree SpaJTow Spizella arborea S,C S, F BAIS Baird's SpaJTow Ammodramus bairdii s F BAOR Baltimore Oriole Icterus galbula s F BASW Bank Swallow Riparia riparia s F BARS Barn Swallow Hirundo rustica s F BCCH Black-capped Chickadee Poe cile atricapillus s F BUA Blue Jay Cyanocitta cristata s F BOBO Bobolink Doli chonyx 01yzivorus s F BRBL Brewer's Blackbird Euphagus cyanocepha/u s S, C s BRTH Brown Thrasher Toxostoma rz,![rum s F BHCO Brown-headed cowbird Molothros ater S,C S, F CANG Canada Goose Branta canad ensis S, C s CEDW Cedar Waxwing Bomby ci/la cedrorum s F CHSW Chimney Swift Chaetura pe/agica s F CHSP Chipping SpaJTow Spizella passerina S, C F CCSP Clay-colored SpaITow Spizella pa/Iida S,C F COGR Common Grackle Quiscula quisca/us S,C S,F COSN Common Snipe Ga/linage gallinago S, C S,F COYE Common Y ellowthroat Geothlypis trichas s F COHA Cooper's Hawk Accipiter cooperii s F DEJU Dark-eyed Junco Junco hyemaf is S, C s DICK Dickcissel Spiza americana s F
64 Table 1. Continued AOU Code Commo n Name Species Name Crop Migration Period DOWO Downy Woodpecker Picoides pubescens s F EAKI Eastern Kingbird Tyrannus tyrannus S,C F EVGR Evening Grosbeak Coccothraustes vespertinus s F FISP Field SpaITow Spizella pus ilia S, C S,F FOSP Fox Sparrow Passerella iliaca s F FRGU Franklin's Gu ll Larus pipixcan C F GRSP Grasshopper Sparrow Ammodramus savannarum s F GRAP Gray Partridge Perdix perdix S,C S,F HAWO Hairy Woodpecker Picoides villosus s F HASP Harris' s Spa1Tow Zonotrichia querula s F HOLA Horned Lark Eremophila alpestris S,C S, F HOFI House Finch Carpodacus mexicanus s F HOSP House SpaITow Passer domesticus S,C S,F HOWR House Wren Troglodytes aedon s F KILL Killdeer Charadrius vociferus S,C S, F LALO Lapland Longspur Calcarius lapponicus s,c S,F LASP Lark SpaITow Chondestes grammacus C F LCSP Le Co nte 's SpaITow Ammodramus leconteii s F USP Lincoln's Sparrow Melospiza lincolnii s F LSGO Lesse r Snow Goose Chen caerulescens caeru lescens C s MALL Mallard Anas platyrhy nchos S,C s MAWR Marsh Wren Cistothorus palustris s F MODO Mourning Dove Zenaida macroura S, C S,F MOWA Mourning Warbler Oporornis philadelphia s F NAWA Nashville Warbler Vermivora ruficapilla s F NSTS Nelson's Sharp -tailed Sparrow Ammodramus nelsoni s F NOFL Northern Flicker Colaptes auratus S, C S,F NOHA Northern HaITier Circus cyaneus S,C S,F
65 Tab le 1. Continued AOU Code Common Name Species Name Crop Migration Period NOPI No11hern Pintail Anas acuta C s F NRWS Northern Rough-winged Swallow Stelgidopteryx serripennis s F NOWA Northern Waterthrush Seiurus noveboracensis s F OCWA Orange-crowned Warbler Vermivora celata s F OROR Orchard Oriole f cterus spurius s F PAWA Palm Warbler Dendroica palmarum s F PUFl Purple Finch Carpodacus pu,pureus s S, F RWBL Red-winged Blackbird Age lius phoenecius S, C S, F RNEP Ring-necked Pheasant Phasianus colchicus S,C S,F RODO Rock Dove Columba livia s F RBGR Rose-breasted Grosbeak Pheycticus !udovicianus s RCKI Ruby-crowned Kinglet Regulus calendula s F S,F RTHA Red-tailed Hawk Buteo jamaicensis C F RTHU Ruby -throated Hummingbird Archi /ochus colubris S, C SACR Sandhill Crane Grus canadens is C s S,F SAYS Savannah Sparrow Passercu/us sandwiche nsis S,C SEWR Sedge Wren Cistothorus platensis s F F SSHA Sharp-shinned Hawk Accipiter striatus s S,F STGR Sharp-tailed Grouse Tympanuchus phasianellus s,c STSP Sharp-tailed Spa1Tow Ammodramus nelsoni s F F SMLO Smith's Longspur Ca/carius pictus s F SNBU Snow Bunting P/ectrophenax nivalis C S, F SOSP Song Spa1Tow Me/ospiza melodia S,C F SORA Sora Porzana carolina s F SPPl Sprague's Pipit An1hus spragueii s F SWHA Swainson's Hawk Buteo swainsoni s SWSP Swamp Sparrow Melospiza geogiana s F TEWA Tennessee Warbler Vermivora peregrina s F
66 Tab le 1. Continued AOU Code Common Name Species Name Crop Migration Period TRES Tree Swallow Tachycineta bicolor S,C F VESP Vesper Spanow Pooecetes gramineus S,C S, F VlRA Virginia Rail Ralf us limicola s F WEKI Western Kingbird Tyrannus verticalis s F WEME Western Meadowlark Sturne/la neglecta S,C S,F WCSP White-crowned Sparrow Zonotrichia leucophrys s F WTSP White-throated Sparrow Zonotrichia albicollis S,C F WIFL Willow Flycatcher Empidonax trail/ii s F YWAR Yellow Warbler Dendroica petechia s F YBFL Yellow-bellied Flycatcher Empidonax jlaviventris S,C F YHBL Yellow-headed Bla ckbird Xanthocephalus xanthocephalus S,C S, F YRWA Yellow-rumped Warbler Dendroica coronata s F
67 Seventy-eight species exceeding 22 In sunflower , Schaaf (2003) nonblackbirds /ha were observed in identified 49 species foraging in field sunflower in the fall (Schaaf 2003 , Hagy interiors and 61 species on interiors and 2006) and 29 species at 2.6 field edges combined . Avian density nonblackbirds /ha were observed in the averaged 22.3 birds/ha m 2001 m spring (Galle 2006) . Galle (2006) found that commercial sunflower. Hagy (2006) blackbirds, passerines , Homed lark observed 58 different species , 38 in WCSP, (Eremophila alpestris) , Lapland longspur 42 in commercial sunflower , and 28 in all (Calcarius lapponicus) , and all bird guilds other crop fields. Nonblackbird densities had higher abundances in sunflower than averaged 4.3 birds /ha in commercial other crop fields. Hagy (2006) omitted non sunflower , 6.2 birds/ha in WCSP , and 1.8 sunflower crop fields from habitat analysis birds /ha in non-sunflower crop fields . reasoning that non-sunflower provide poor Collectively , avian density differed habitat for birds when compared to significantly for all birds combined (P = sunflower and bird observation numbers 0.05) across all field types in 2004 and 2005 were insufficient in non-sunflower crops to (Hagy 2006). Hagy (2006) showed that conduct a reliable analysis. Galle (2006) average nonblackbird densities were higher detected homed larks, Lapland longspurs , in ripening sunflower ( 4.3 birds/ha) and red-winged blackbirds most commonly compared with wheat (2.9 birds/ha), com in cropped fields; whereas , Hagy (2006) (2.3 birds /ha), soybean (2.1 birds/ha), observed red-winged blackbird , yellow flaxseed (l.7 birds /ha), and canola (< l headed blackbird , and white-throated birds /ha). Galle (2006) observed similar sparrow (Zonotrichia albicollis) most trends in the spring. commonly in crop fields.
5 ~ pring ] 4.5 l ■ Fall 4
3.5
Ill 3 .s:::.
v, 2.5 "1J... :0 2
1.5
0.5
Sunflower Small grain Corn Soybean
Figure 1. Nonblackbird use of crop fields in the spring (March and April) and fall (August - October) in North Dakota.
68 DISCUSSION (WCSP) to minimize blackbird damage and Schaaf (2003), Galle (2006), and harassment costs in commercial sunflower Hagy (2006) showed that agricultural fields fields. Lure crops, for reducing wi ldlife are important foraging habitats for birds damage to commercial agriculture , have during fall and spring migration in North been shown to be effective when carefully Dakota. Moreover, of those crop habitats planned and manageed (Gustad 1979, avai lable to migratory birds, sunflower may Cumm ings et al. 1987). Harassing migratory have a disproportional importance to birds birds increases grain wasting and may have compared to percent coverage in the state. negative effects on the birds themselves For example , in 2005, wheat (42%), (Gustad 1979). Reduced hazing and other soybeans (19%) , com (9.3%), barley (8.3%), repulsion methods could save farmers time and sunflower ( 4.5%) were the five major and money while improving sunflower row-crops in North Dakota (NASS 2005). habitat quality for migratory birds. Nutritional value (Diaz 1990) and energy potential (Hagen 2006) are likely the MANAGEMENT IMPLICATIONS primary reasons for the birds ' selection of We conclude that WCSP aimed at sunflower. Sunflower fields often have a reducing wildlife damage to commercial higher density of weeds compared to agriculture can be an important part of an herbicide resistant row crops such as overall integrated pest management plan. soybean and com (Krapu et al. 2004). Limited traditional control methods m Common "weeds" in sunflower may be commercial sunflower to avoid blackbird attractive to granivorous birds, providing "establishment" combined with well placed increased incentive to visit sunflower fields lure plots and initiatives such as the cattail (Cummings and Avery 2003). Other studies management program may help reduce have suggested that complex vegetation blackbird damage in areas that are strncture and diversity within fields can predisposed to depredation (Linz et al. improve wildlife habitat in agricultural 1992). WCSP can potentially help meet landscapes , especially to neotropical blackbird nutrition needs, act as migratory migratory birds (Otis and Kilburn 1988, bird stopover havens , and reduce damage to Koford and Best 1996) . commercial sunflower acreages in North Sunflower is a valuable agricultural Dakota. Additionally , WCSP that are not commodity for both migratory birds and tilled until spring might provide an producers which can sometimes lead to important habitat for resident and migrating significant conflict and costs for both birds during winter and spring migration. groups . Ironically, 82 million Americans fed wild birds using at least $ l billion in LITERATURE CITED bird seed in 1985. Today , estimates have ASKINS, R.A. 1993. Population trends in been as high as $10 billion in bird seed grassland, shrub land, and forest birds in purchases, a major constituent of which is eastern North America . Current oilseed sunflower (O 'Brien et al. 2001). Ornithology I l : 1-34. Thus , sunflower producers and researchers 1999 . History of grassland birds in eastern No1th America. Studies in Avian are faced with the dilemma of keeping bird Biology 19:60- 71 . food away from birds . __ . 2000 . Restoring North America's Birds: As blackbirds can become an Lessons From Landscape Eco logy. Yale economical burden to producers , we suggest University Press, New Haven, CT. using lure plots of oilseed sunflower
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