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Upper Midwest Environmental Sciences Center

The Long Term Resource Monitoring Program

An element of the Upper Mississippi River Restoration - Environmental Management Program

Importance of the Upper Mississippi River Forest Corridor to Neotropical Migratory Birds

Upper Mississippi River Restoration - Environmental Management Program U. S. Army Corps of Enineers


Neotropical and short distance migrant birds spend 2-4 months per year in transit between summer and winter habitats (Keast and Morton 1980). There is growing concern and interest in bird habitat use during migration so that conservation efforts can target important migration habitat and landscapes (Moore et al 1995, Petit 2000).

Riparian areas in the arid west have long been touted as important habitats for breeding neotropical and short distance migrant birds (Knopf et al. 1988, Finch 1989, Finch and Ruggerio 1993, Rosenberg et al. 1991) and more recently for these birds during migration (Finch and Yong 2000, Flannery et al. 2004, Skagen et al. 2005). But in eastern deciduous forest landscapes, neotropical and short-distance migrant birds may not use riparian areas preferentially over upland habitats during spring (Rodewald and Matthews 2005). However, Upper Mississippi River System wetlands, backwaters, and extensive forests on the floodplain, and the adjacent bluff slope and bluff top forests form a nearly continuous habitat corridor through the central portion of the United States which is otherwise largely converted to row-crop agriculture. This continuity of forest along the UMR in a highly agricultural portion of the US may serve as a corridor for migrating birds. Thus, it is thought that the Mississippi and Illinois River corridors provide an important link between southern wintering grounds and northern breeding grounds for neotropical and short distance migrant birds.

Human made structures such as the lock and dam system, HREPS, wind power generators, and cellular telephone towers can modify habitats that may be important for songbirds during migration. Negative modifications may interfere with migration by eliminating or reducing the quality of habitat birds need for rest and refueling resulting in decreased survival and productivity. Modifications to aid navigation on the Upper Mississippi River System over the past 100 years have resulted in changes to the natural hydrographs and the rivers' connectivity to the surrounding landscape. These modifications have resulted in changes in tree species composition, as well as distribution, structure, and abundance of floodplain forests. National Wildlife Refuges and Corps of Engineer Districts spend hundreds of thousands of dollars annually on forest restoration and management within the floodplain and in the adjacent uplands. To date, projects have been site specific and there have been few attempts to take a landscape approach to siting projects or to monitor the results of individual forest restoration projects. More importantly, restoration efforts have occurred without the benefit of knowing where migrant birds (and breeding birds for that matter) tend to congregate, what habitats they use, when they arrive and depart, what their physiological conditions are in relation to resting and refueling habitats, and if there are any physical barriers to migration. As a result there is little information about habitat requirements of birds during migration and timing of migration to use in the development of habitat restoration projects, habitat management strategies, siting of communication towers and wind power generation projects, and other types of developments. The U.S. Fish and Wildlife Service and the Corps of Engineers would benefit greatly from a system-wide evaluation of habitat use by spring songbird migrants over habitats along the Mississippi River System up to the Great Lakes and Boreal Transition Regions.

Relevance of research:

Migration ecology of landbirds simply is not well understood, yet. Although it has been assumed that UMR corridor is important for migrating songbirds, this has never been demonstrated. Further, there are few data on how neotropical and short distance migrant birds (other than waterfowl) use the corridor. In addition, there is no information regarding the existence, location and habitat type of specific stopover sites, and if migrating birds use the riverine habitats preferentially over upland habitats. It may be that birds use the full length of the river floodplain and adjacent uplands forests during migration without regard or with little detectible regard to specific habitat types or locations.

The importance of the floodplain forests of the river corridor in relation to the adjacent upland forest remnants needs to be documented along the UMRS. Different species of birds may be using different types of forests or different forest types may provide better food resources for migrants than others. Land managers along the UMRS would benefit greatly from the development of guidance on where to initiate restoration efforts, if certain desirable habitat conditions can be managed for, and what bird species are most likely to benefit from forest management and restoration. The Driftless Area and the Upper Mississippi River System may be important for migrating Wood Thrush, Veery, Golden-winged Warbler, Connecticut Warbler, Cerulean Warbler, Rose-breasted Grosbeak, and Black-billed Cuckoo-species of conservation concern in Partners in Flight Conservation Regions 16 and 20 (Upper Great Lakes Plain and Boreal Hardwood Transition) (Knutson et al. 2000, PIF 20, [date accessed February 2005).

Ten years of NEXRAD images are available for the upper Midwest covering the UMRS. Others have studied the utility of NEXRAD for monitoring bird movements and potential for detecting migration habitat "hot spots." It is possible to use this technology to help UMRS resource managers locate potentially important habitat areas for migrating birds. Our goal is to examine the available NEXRAD data and collect NEXRAD data for 2006-2007 and combine that information with land use/cover GIS data, data from ground based surveys and bird netting/banding to better understand movement patterns, species composition, physiological condition, and habitat associations of migratory birds from the Mark Twain National Wildlife Refuge Complex north to the upper reaches of the Upper Mississippi Wildlife and Fish Refuge Complex and east along the Illinois River Wildlife and Fish Refuge Complex. Land managers and industry will benefit from the databases and tools developed from this work to optimize the siting of future energy projects, cellular telephone towers, and habitat restoration and enhancement projects.

We will address several questions with a fully funded study. Are there habitat hot spots for migrating landbirds associated with the UMRS? Do species and abundances of migrating birds in upland and floodplain forests differ? Does body condition of migrating birds differ between floodplain forest and upland forest? What are the local forest habitat structure variables that may influence species composition or body condition differences? What are the habitat features of migration hotspots that may be amenable to management to increase the habitat suitability of other locations?
Because the landscapes surrounding the UMR vary greatly from St. Louis, MO to Minneapolis, MN, the relative importance of riverine habitats may differ along the river. For example the relative importance of the river in the Driftless region (sampled by Pools 6-9) versus the Prairie Peninsula region (sampled by Pools 16-18). Migrating songbirds may more heavily use the floodplain in the Prairie Peninsula region as compared to the Driftless Area, where forested habitats and surface water away from the floodplain is more abundant. Furthermore, energetic needs of migrant birds may be affected by distance traveled and we may detect patterns in habitat occupancy and body condition along the length of the river as the season progresses.


This proposal can be funded at 5 different levels. Methods for the full study (ground surveys, bird banding, GIS and radar data layering:1st budget option) follow in the next few paragraphs and will allow us to address all the research questions presented above to represent the entire Impounded Reach of the UMR (Pools 6-9, Pools 16-18 and Pools 24-26). Lower levels of funding will necessitate a lower level of effort. The 2nd budget option includes ground surveys along the UMRS, but increases the study area to include Pools 24-26. The 3nd budget option includes ground surveys along around Pools 6-9 and Pools 16-18, but adds a banding effort in Pools 16-18 (banding in Pools 6-9 is supported by UMESC with other funds). The 4th level of funding supports ground based surveys in Pools 6-9 and Pools 16-18 (This was the funding level for 2006). The 5th budget option includes radar and GIS data but includes the ground survey effort for only a small area of the UMRS, Pools 6-9, where preliminary work started in 2005. Options 2-5 also have a GIS and radar data component.

Archived weather surveillance radar (WSR-88D, or NEXRAD) data will be acquired from 10 locations from 1995-2005 (Minneapolis, MN, La Crosse, WI, Davenport, IA, St. Louis, MO, Des Moines, IA, Lincoln, IL [Central Illinois], Milwaukee, WI, Duluth, MN, Paducah, KY, and Little Rock AR). Data from radar sites distant from the UMR will be used to detect any possible larger scale patterns in bird migration that could indicate the relative use of the UMR. From each radar location we will examine images from April and May for the 1 hour period following dusk, the period of "exodus" for migrating landbirds. We will also acquire weather information for each radar scene. Potential important bird habitat will appear as rapidly expanding nearly circular areas of high reflectivity emanating from focal land areas (Gauthreaux and Belser 2005).

On the ground, migrating birds will be sampled using line transect surveys (i.e., Rodewald and Matthews 2005, Hanowski et al.1990) and mist netting/banding (Ralph et al. 1993). The ground-based study area includes the UMRS (Mississippi and Illinois Rivers) floodplain and uplands up to 16km (10 miles) from the floodplain. Ground study sites will be Pools 6-9 in the Upper Mississippi National Wildlife and Fish Refuge, Pools 16-18 and Pools 24-26 which includes portions of the Mark Twain National Wildlife Refuge Complex (see Study Area, below).

Survey transect locations will be randomly selected and distributed equally among floodplain and upland forests. The final list of random sites to be included will be selected based on accessibility and logistical considerations. Each transect will be 150m long. Surveyors will record all birds seen and heard along transects, as well as estimated distances to birds, while walking at a pace of approximately 1 km/ hour. Thus, each transect should take about 10 minutes to complete. Transects will be surveyed two to three times per week from early April until the end of May. A total of 30 survey transects with good access can reasonably be surveyed by a crew of four in a single morning with ideal weather. After each survey, the degree of leaf-out in canopy, subcanopy, and understory trees and shrubs will be recorded (Rodewald and Matthews 2005). Additionally, time of day and simple weather data will be collected during each survey, such as temperature, wind, sky and precipitation conditions. In early June, after surveys are completed, detailed information about forest structure will be collected at 50m intervals along the transect. Point-center quarter sampling will be used and the species and estimated height, dbh, and distance to the center of the quarter will be recorded for canopy and understory trees. The number of snags within 25m of the sample point over 10cm dbh will be counted. Canopy and subcanopy heights will be estimated from a tree that represents the average in each sampling plot, using a clinometer.

Banding stations will be set up in several of these random locations, but they must be accessible and have suitable habitat for setting up mist nets (an abundance of low shrubby vegetation). Thus sites to be selected for banding will be accessible by 4 wheel drive vehicle or boat and all possible net locations must be in close proximity, which rules out extremely small patches of forest (which may be selected randomly for transect surveys). Pairs of floodplain and upland banding stations will be run simultaneously, and station pairs will be located in similar latitudes. Each pair of banding stations will be run at least once a week from early April through the end of May using standard banding protocols (USGS Bird Banding Manual; Smith et al. 1997, DeSante et al. 2005). Banding data will be reported to the Bird Banding Laboratory within 45 days of conclusion of the field portion of the study. Support staff will be used to extract birds from the nets and will be trained in banding ethics, proper extraction, restraint, and handling techniques (Smith et al. 1997, DeSante et al. 2005). Staff will be trained to use the following holds safely: bander's grip, leg hold and ice cream cone grip (Smith et al. 1997). Each banding station will consist of 10, 12m long by 3 meter high, 4-shelved 30mm mist nets. Nets will be opened at sunrise and closed 6 hours later. Nets will be checked every 40 minutes. Nets must be placed near shrubby vegetation on a site, or birds can see the nets and will avoid capture. Along with recording species, sex, and body condition (Pyle 1997, Eggler and Williams 2000), we will collect blood from selected species to evaluate blood chemistries (Guglielmo et al. 2002, McWilliams et al. 2002). For example, plasma lipid profiles can indicate whether a bird is gaining or loosing weight. The degree of leaf-out will be recorded during each banding session at the location of each odd numbered net. More detailed habitat data will be collected at banding stations in early June using the MAPS protocol (De Sante et al. 2005). Weather conditions at banding stations will be recorded hourly during each banding session.

Along with randomly selected survey areas, locations of some survey transects and banding stations will be based on any evidence of migration habitat "hotspots" as detected from archived NEXRAD. Should any hotspots in or on the UMRS be detected in archived radar data, we will sample in the location and at random points within 5km of the presumed hotspot, including upland and floodplain forests within that 5km radius.

We additionally propose to continue developing the use of radar technology in combination with the ground surveys of migratory songbirds and in association with the new USGS/FWS interagency program to advance migratory bird conservation and management using weather surveillance radar technology (Dr. Rick Kearney, USGS, Reston, VA, Pers. comm). We will continue to compile data in our GIS database that includes of 1) radar imagery, 2) the Long Term Resource Monitoring Program of the Upper Midwest Environmental Sciences Center's landuse/landcover data and refuge landcover data, 3) landuse/landcover data from the USGS' National Landcover Database (NLCD) and GAP databases to fill in gaps in the LTRMP's coverage, and 4) data from ground-based surveys of migratory bird species, timing, duration, and habitat use during spring. We currently are working up the 2006 data and plan to examine the utility of the combined datasets in identifying important stopover locations. Increased funding will allow us to step up to an Upper Mississippi River effort with our final goal of conducting a basin-wide effort that includes the Middle and Upper Mississippi, Illinois, Ohio and Missouri Rivers, should further funding be obtained from other sources as well.

The network of 151 NEXRAD radar stations in the contiguous United States presents a unique (and free) opportunity to monitor bird migration over this broad area. We propose to use two types of NEXRAD products (base reflectivity and base velocity images) to delimit stopover areas during spring and fall migration in a few locations of the Upper Mississippi Refuge Complex wherein we have Long Term Resource Monitoring Program and NLCD data and on-going spring migration surveys (USGS-UMESC) along the Mississippi Illinois River corridors. A second test site will include the Mark Twain Refuge Complex and a third site, as time and funding permits, within the Illinois River Refuge Complex. Reflectivity images will be processed to emphasize areas of relatively high bird density and the resulting imagery will be converted to rectangular raster format and imported into ArcInfo. The maps showing relative density of birds departing from stopover areas can then be compared with land cover maps based on classified Landsat data. Where available, data from ground surveys will be used to interpret the radar images and to examine habitat associations and the physiological condition of birds for more detail. Only a few radar studies have been conducted around the Great Lakes (D. Bonter unpubl. data; R.H. Diehl unpubl. data) but few have been published (Belser and Gauthreaux 2005; Diehl, et al. 2005) and we propose to work with these scientists to incorporate these data as we begin our efforts.

Study Area:

We will begin our focus for the radar work one section each of on the Upper Mississippi National Wildlife and Fish Refuge, Mark Twain National Wildlife Refuge, and Illinois River National Wildlife and Fish Refuges-beginning with locations wherein we have over 10 years of Long Term Resource Monitoring Program landcover and other data from several studies of migratory birds and then moving to other areas of the corridor. Ground surveys for migratory birds will be conducted along the Upper Mississippi on floodplain forests and upland forests within 10 miles of the river on federal, state and private land (with permission).

Option 5 includes bird banding and transect surveys in and near the UMR between Winona, MN and Lansing IA, only. We will continue to develop the NEXRAD analyses for the entire UMR floodplain.

Literature Cited:

DeSante, D.F., K. M. Burton, P. Velez, and D. Froehlich. 2005. Instructions for the establishmentand operation of constant-effort bird-banding stations as part of Monitoring Avian Productivity and Survivorship (MAPS) Program. The Institute for Bird Populations, Point Reyes Station, California.

Diehl, R.H., R.P. Larkin, and J.E. Black. 2005. Radar observations of bird migration over the Great Lakes. The Auk 120:278-290.

Eggler, O., and T. D. Williams. 2000. Seasonal, age, and sex-related variation in fatty acid composition of depot fat in relation to migration in Western Sandpipers. The Auk 117: 110-119.

Finch, D. M., and W. Yong. 2000. Landbird migration in riparian habitats of the Middle Rio Grande: a case study. Studies in Avian Biology 20: 88-98.

Finch, D.M. 1989. Species abundances, guild dominance patterns and community structure of breeding riparian birds . Pp. 629-645 In R. R. Sharitz and J. W. Gibbons (editors). Freshwater wetlands and wildlife: perspectives on natural managed and degraded ecosystems. DOE-CONF 8603101, Office of Scientific and Technical Information. U.S. Department of Energy, Oakridge, Tennessee.

Finch, D. M. and L. F. Ruggiero. 1993. Wildlife habitats and biological diversity in the Rocky Mountains and northern Great Plains. Natural Areas Journal 13: 191-203.

Gauthreaux, S.A.Jr., and C.A. Belser. 2005. Radar ornithology and biological conservation. The Auk 120:266-277.

Guglielmo, C.G, P. D. O'Hara, and T. D. Williams. 2002. Extrinsic and intrinsic sources of variation in plasma lipid metabolites of free-living Western Sandpipers (Calidris mauri). The Auk 119: 437-445.

Hanowski, J. M., G. J. Niemi, and J. G. Blake. 1990. Statistical perspectives and experimental design when counting birds on line transects. The Condor 92:326-335.

James, F. C., and H. H. Shugart, Jr. 1970. A quantitative method of habitat description. Audubon Field Notes 24:727-736.

Keast, A., and E.S. Morton (editors). 1980. Migrant birds in the neotropics: ecology, behavior, distribution, and conservation. Smithsonian Institution Press. Washington, D.C.

Knopf, F. L., J. A. Sedgwick, R. W. Cannon. 1988. Guild structure of a riparian avifauna relative to seasonal cattle grazing. Journal of Wildlife Management. 52: 280-290.

McWilliams, S. R.,S. B. Kearney, and W. H. Kasarov. 2002. Diet preferences of warblers for specific fatty acids in relation to nutritional requirements and digestive capabilities. Journal of Avian Biology 33: 167-174.

Moore, F. R., S. A. Gauthreaux, Jr., P. Erlinger, and T. R. Simons. 1995. Habitat requirements during migration: important link in conservation. Pp. 121-144 in T. E. Martin and D. M. Finch (editors). Ecology and management of neotropical migratory birds: a synthesis and review of critical issues. Oxford University Press, New York, NY.

Nott, P., D. F. De Sante, and N. Michel. 2003. Monitoring avian productivity and survivorship (MAPS) habitat structure assessment (HSA) protocol: describing vertical and horizontal habitat patterns at MAPS stations. Institute for Bird Populations, Point Reyes, California.

Pyle, P. 1997. Identification guide to North American birds. Slate Creek Press, Bolinas, CA.

Ralph, C. J., G. R. Geupel, P. Pyle, T. E. Martin, and D. F. DeSante. 1993. Handbook of field methods for monitoring landbirds. Gen. Tech. Rep. PSW-GTR-144. Albany, California: Pacific Southwest Research Station, Forest Service, U.S. Dept. of Agriculture, 41 pp.

Rodwald, P. G., and St. N. Matthews. 2005. Landbird use of riparian and upland forest stopover habitats in an urban landscape. The Condor. 107:259-268.

Rosenberg, K. V., R. D. Omart, W. C. Hunter, and B. W. Anderson. 1991. Birds of the lower Colorado River valley. University of Arizona Press, Tuscon Arizona.

Skagen, S. K., J.F. Kelley, C. Van Riper III, R.L. Hutto, D.M. Finch, D.J. Krueper, and C.P. Melcher. 2005. Geography of spring landbird migration through riparian habitats in southwestern North America. The Condor 107:212-227.

Smith, H., J. McCracken, and D. Sheperd. 1997. The Bander's Safety Handbook: A North American Bird Banders Guide to Safe and Ethical Field Procedures. Unpub. Rept. Contribution #68 of the Institute for Bird Populations, Pt. Reyes, CA. 90 pp.

Principle investigator: Eileen Kirsch, USGS-UMESC; 2630 Fanta Reed Road, La Crosse, WI 54603, 608-781-6226; 608-783-6066 (fax);

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