No abstract

No abstract

Loss of habitat is one of the primary factors affecting population declines of grassland birds, and recovery efforts have focused on increasing the amount of grassland habitat in the landscape. Assessing the value of habitat restorations for grassland birds is an essential component of grassland bird conservation. We compared grassland bird habitat use, reproductive success, nestling growth rates, nestling baseline corticosterone, and blood glucose levels among restored grasslands planted with seed mixes of varying plant species diversity. In addition, we tested the ability of a conspecific song playback system to attract Henslow's sparrows to previously unoccupied restored habitat. We selected 4 grassland planting types, cool-season, warm-season (newly planted and mature), and high diversity for our study to encompass the range of planting mixtures typically available to land managers. The most common bird species we encountered were Bobolink (Dolichonyx oryzivorus), Common Yellowthroat (Geothlypis trichas), Red-winged Blackbird (Agelaius phoeniceus), and Sedge Wren (Cistothorus platensis). Bird densities overall were not consistently higher or lower in any one of the 4 planting types. Bobolink densities, however, were higher in Cool-season fields than in any of the other field types. Models of the relationships between bird density/bird species richness and habitat characteristics revealed that both vegetation characteristics and food resources were important in explaining grassland bird densities. Our habitat models showed that different species, even those within a species category, were influenced by different habitat characteristics. Given the importance of cool-season, nonnative grass plantings for Bobolinks in our study, consideration must be given to the impact that elimination of these plantings may have on the future of Bobolink populations. Redwinged Blackbird nest survival was influenced by year, visual obstruction, and variation in v the availability of invertebrate food resources throughout the nesting season. We found evidence for a difference in daily nest survival among planting types (P=0.06). Specifically, estimated nest survival was more than twice as high in mature warm-season fields (36%) than in cool-season fields (14%). Red-winged Blackbird nestling size at fledging differed among grassland planting type. Male nestlings were larger than females at fledging with regard to mass, wing, and tarsus measurements. Nestling growth rates did not differ either among grassland restoration planting types or between sexes. Invertebrate food resource availability did not appear to affect growth rates of nestling Red-winged Blackbirds. Redwinged Blackbird nestling baseline corticosterone levels were lower in the warm-season planting type than in either cool-season or high diversity plantings. We found no evidence of differences in baseline corticosterone levels or blood glucose levels between males and females. We found no relationship between baseline corticosterone levels and body mass or between base...

After translocation a female greater prairie-chicken (Tympanuchus cupido pinnatus) traveled over 3988 km between 5 April 2013 and 20 June 2014. The bird traveled a mean distance of 21.5 km per day during the spring (median distance per day 22.2 km; range 0-115 km per day) moving through portions of four states. Nine other marked birds traveled a mean distance of 336 km and a mean distance per day of 7.5 km during the spring (median distance per day 4.6 km; range 0-92 km per day). This is the first record of movements of this magnitude by a greater prairie-chicken. This report highlights the use of recent advances in satellite/GPS telemetry methods for advancing our knowledge of wildlife movements.

Reproductive success of mallards (Anas platyrhynchos) is influenced by distribution and amount of wetlands and grasslands on the landscape during the breeding season. Most studies of mallard reproductive success have been conducted in areas with high wetland densities and large tracts of grasslands. We investigated nest survival of mallards in intensively cropped northern Iowa, USA, where wetland and grassland habitats were highly fragmented. We radiotracked female mallards nesting during 1998-2000 and located 318 nests in 6 types of land cover. Overall daily survival rate of nests was 0.945 AE 0.003 standard error (SE), corresponding to an estimated nest survival rate of 0.14. Hen success (i.e., the probability that an individual female will hatch a nest in one of her attempts) averaged 0.28 AE 0.03 SE. We used a model selection approach to examine covariates that might affect nest survival. Perimeter-to-area ratio (PAR) of the nest patch was the most important predictor of daily nest survival, with nest survival decreasing with increasing PAR. A greater percentage of nests hatched (18%) in habitats with low perimeter-to-area ratios (e.g., pastures, hayfields, Conservation Reserve Program fields, and managed grasslands) compared with habitats with high PAR (11%) such as drainage ditches, road-side ditches, fencerows, and waterways. Managing habitat in this region to increase mallard nest survival will be challenging, given the propensity of mallards to nest in linear habitats. If the climate change projections materialize in the 21st century, the southeastern portion of the Prairie Pothole Region could become a much more important breeding area for midcontinent mallards. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.