Eight Novel Microsatellite Loci in a Declining Grassland Songbird, the Bobolink ().

Microsatellite loci in non-coding regions of nuclear DNA provide an important tool for genetic diversity research, particularly when comparing relatedness between individuals. While microsatellites have been developed for several species within the Blackbird family (), no species-specific microsatellite primers for genetic analysis of Bobolinks () exist. Like many grassland songbirds, Bobolink populations are in decline, and accessible genetic analysis tools are therefore critical for understanding population dynamics.

Agriculture is adapting to phenological shifts caused by climate change, but grassland songbirds are not.

Migratory birds time their migration based on cues that signal resource availability for reproduction. However, with climate change, the timing of seasonal events may shift, potentially inhibiting the ability of some species to use them as accurate cues for migration. We studied the relationship between phenological shifts and reproduction by long- and short-distance migratory songbirds-Bobolinks ( and Savannah Sparrows (.

Heritability and evolvability of morphological traits of Savannah sparrows (Passerculus sandwichensis) breeding in agricultural grasslands.

Heritability and evolvability estimates of adult traits from free-living bird populations can be used to gauge the ability of populations to respond to selection, but are rare due to difficulties in gathering detailed pedigree information. The capacity to respond to selection is particularly important for species occupying managed habitats such as agricultural grasslands because of the potential for humans to accidentally influence traits. We calculated heritability and evolvability of six morphological traits in a population of Savannah Sparrows (Passerculus sandwichensis) breeding in a large agricultural landscape.

Haemosporidian parasite community in migrating bobolinks on the Galapagos Islands.

Bobolinks () migrate from their breeding grounds in North America to their wintering grounds in South America during the fall each year. A small number of Bobolinks stop temporarily in Galapagos, and potentially carry parasites. On the North American breeding grounds, Bobolinks carry a least two of the four lineages recently detected in resident Galapagos birds.

Local parasite lineage sharing in temperate grassland birds provides clues about potential origins of Galapagos avian Plasmodium.

Oceanic archipelagos are vulnerable to natural introduction of parasites via migratory birds. Our aim was to characterize the geographic origins of two Plasmodium parasite lineages detected in the Galapagos Islands and in North American breeding bobolinks (Dolichonyx oryzivorus) that regularly stop in Galapagos during migration to their South American overwintering sites. We used samples from a grassland breeding bird assemblage in Nebraska, United States, and parasite DNA sequences from the Galapagos Islands, Ecuador, to compare to global data in a DNA sequence registry.

Grassland songbird survival and recruitment in agricultural landscapes: implications for source-sink demography.

Population growth and decline are particularly sensitive to changes in three key life-history parameters: annual productivity, juvenile survival, and adult survival. However, for many species these parameters remain unknown. For example, although grassland songbirds are imperiled throughout North America, for this guild, only a small number of studies have assessed these parameters.

Agricultural management affects evolutionary processes in a migratory songbird.

Hay harvests have detrimental ecological effects on breeding songbirds, as harvesting results in nest failure. Importantly, whether harvesting also affects evolutionary processes is not known. We explored how hay harvest affected social and genetic mating patterns, and thus, the overall opportunity for sexual selection and evolutionary processes for a ground-nesting songbird, the Savannah sparrow (Passerculus sandwichensis).

Grassland songbirds in a dynamic management landscape: behavioral responses and management strategies.

In recent decades, earlier and more frequent harvests of agricultural grasslands have been implicated as a major cause of population declines in grassland songbirds. From 2002 to 2005, in the Champlain Valley of Vermont and New York, USA, we studied the reproductive success of Savannah Sparrows (Passerculus sandwichensis) and Bobolinks (Dolichonyx oryzivorus) on four grassland treatments: (1) early-hayed fields cut before 11 June and again in early- to mid-July; (2) middle-hayed fields cut once between 21 June and 10 July; (3) late-hayed fields cut after 1 August; and (4) rotationally grazed pastures. Both the number of fledglings per female per year and nest success (logistic-exposure method) varied among treatments and between species.