Birds should select nest sites that minimize predation risk, but understanding the influence of vegetation on nest survival has proven problematic. Specifically, the common practice of measuring vegetation on nest fate date can overestimate its effect on nest survival, simply because vegetation at hatched nests grows for a longer period of time than vegetation at nests that were depredated. Here, we sampled the literature to determine the prevalence of this bias in studies of duck breeding ecology. We then used survival data collected from ~2,800 duck nests to empirically evaluate evidence of bias in four different vegetation metrics: vegetation density measured when the nest was found, density when the nest was fated, and date‐corrected regression residuals of these two. We also diagnosed the magnitude of vegetation effects on nest survival by restricting our analysis to only nests which were fated contemporaneously (thereby removing potential bias in the timing of measurement). Finally, we examined whether systematic phenological differences exist between vegetation at hatched and depredated nests that have the potential to further obfuscate the relationship between vegetation and nest survival. We found evidence for a true‐positive effect of vegetation density on nest survival that appeared to be inflated when using raw vegetation measurements collected at fate date. However, taken in combination with the literature review, our results suggest that the majority of duck nesting studies have evaluated the role of vegetation on nest survival using a relatively less biased metric—vegetation density when the nest was found. Finally, we found that over the course of a nesting attempt, vegetation increased in density at successful nests, but decreased in density at depredated nests. As a consequence, duck researchers using vegetation data collected when the nest was found may actually be underestimating the magnitude of the effect. This seasonal change potentially points to an important new metric for understanding predation risk, but further experimental research is required to fully eliminate potential biases in the timing of vegetation measurements.

Over the past decade, the United States has seen a rapid increase in oil and gas extraction from areas where resources were previously thought to be unrecoverable, particularly the Bakken shale formation in North Dakota. The Bakken overlaps with the Prairie Pothole Region, the most critical habitat in North America for breeding ducks, where oil and gas extraction through hydraulic fracturing has the potential to impact more than a million duck pairs in the United States alone. Here, we evaluated the effect of oil and gas development on nesting ducks in 2015–2017 across 5 counties in North Dakota. Using data from ~4,000 nests we found that nest survival was higher at sites composed of a higher percentage of grassland, and for nests found closer to major roads. We found no effect of any metric of oil and gas extraction activity on duck nest survival. Using survival-corrected estimates of nest density, we found higher densities of nests closer to roads, but lower nest densities at sites surrounded by more wells. Our top-ranked model indicated that nest density was predicted to decline by 14% relative to sites with no development, given the average number of wells (3.15 wells) within 1,500 m of a site. However, within a nesting field, we found no evidence that ducks were avoiding petroleum-related infrastructure at smaller spatial scales. Our results indicate mixed effects of oil and gas development on nesting waterfowl, and highlight both the resiliency of dabbing ducks to environmental change and the need for additional research on other aspects of duck breeding biology.

As breeding populations of many grassland bird species decline, assessments of breeding habitat selection and reproductive success can provide useful insight into breeding ecology to support conservation delivery. Here, we demonstrate the use of nest location and survival data collated from 20 data contributors across the Prairie Pothole Region of the United States and Canada over a half century to examine habitat selection and nest survival of Western Willets (Tringa semipalmata inornata) and Marbled Godwits (Limosa fedoa), hereafter "willets" and "godwits." Both willets and godwits selected territories with less variation in vegetation height and topography relative to available locations. Willets selected nest sites that were flatter, closer to wetlands, and had shorter vegetation than Marbled Godwits, while godwits selected territories with greater wetland cover and shorter vegetation. Despite differences in finescale habitat selection, willets and godwits experienced similar daily nest survival rates and ecological drivers of nest survival. Nest success for the entire nest exposure period was estimated to be 0.521 (95% credible interval: 0.39-0.65) for willets and 0.562 (95% credible interval: 0.42-0.70) for godwits. Nest survival for both species increased with nest age and distance from the nest to the nearest wetland edge, while nest survival of godwits declined with conspecific breeding density. These relationships, as well as a weaker positive effect of microtine rodent abundance on nest survival, resembled drivers of upland nesting waterfowl reproductive success in the same region, which we attribute to their shared nest predators. Nest survival analyses of our collaborative dataset required substantial consideration of biases emerging from different data collection methods, ultimately reaffirming the importance of nest aging techniques in proper nest fate assignment. Analysis of compiled datasets using emerging analysis methods will continue to grow our understanding of the ecology of data sparse species.

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Buffleheads (Bucephala albeola) predominantly nest in the boreal forests and aspen parklands of Canada and Alaska. Historically, Buffleheads were common migrants but not summer residents in Minnesota. However, recent observations in Minnesota and surrounding states suggest increased breeding activity in the region. In 1978, the first Bufflehead brood in Minnesota was recorded at East Park Wildlife Management Area. Annually, Agassiz National Wildlife Refuge (NWR) has conducted pair and brood surveys, with species-specific records available from 1990 to 2014. We report an increase in numbers of Bufflehead breeding pairs and broods at Agassiz NWR and new pair observations in surrounding areas.