Estimating space use in organisms is important for understanding their basic ecology and for effective conservation and management. Typically, areas that are guarded or defended are referred to as territories, whereas home ranges encompass space use for all activities. We estimated territory and home range size for the eastern Grasshopper Sparrow, a subspecies of conservation concern, at two sites near the northern limit of the breeding range near Ottawa, Ontario, Canada. The average territory size (1.05 +/- 0.16 ha) was significantly smaller than the average home range size (2.69 +/- 0.51 ha). Similarly, territories overlapped home ranges by an average of 55%, suggesting that visual observations alone may limit our understanding of space use in this species. Territories and home ranges averaged larger on a natural limestone alvar compared to a pasture study site. While space use averaged higher at the alvar site, birds at the pasture site compensated for smaller territories by overlapping more with neighboring conspecifics. Given high aggregation and overlap in space use in this study, we discuss our results in the context of improving survey count accuracy and conservation outcomes in this declining species.

Wildfire is an important natural disturbance shaping the boreal forests of North America. Not surprisingly, many species have adapted to benefit from the structural or functional changes in response to fire. Of these post-fire species, the Northern Hawk Owl (Surnia ulula caparoch) is one of the least studied species on the continent. We surveyed 18 recent fires in the boreal forest region of Alberta, Canada, ranging in age from 1 to 14 years post -fire, to improve our understanding of post-fire habitat relationships for this species. Hawk owls were present in fires ranging from 2 to 11 years post-fire, and occupied burns ranging in size from 1,000-272,000 ha. Hawk owls were strongly associated with areas of older deciduous-dominated forest, based on pre-fire forest inventory. Hawk owl responses to pre-fire forest age structure and composition were consistently stronger at the 1000 m radius (home range) extent than the 400 m (nest site) extent. We also found hawk owls responded differently to time since fire, with an immediate (e.g. 2-6 yr) response to low severity fire and a delayed (10-11 yr) response to high severity fire. We recommend future surveys for this species be conducted earlier in the day, ideally within a few hours of sunrise, based on the timing of detection in this study. Finally, the retention of large patches (e.g. > 300 ha) of older, deciduous-dominated habitat within post-fire forests may be an important management consideration for the conservation of hawk owls and other post-fire species.

Conservation of migratory species depends on an understanding of the drivers causing population declines across the annual cycle. Since it is difficult to track the entire annual cycle for long-distance migrants, measurements from part of the cycle may provide insights into overall drivers. Barn Swallows (Hirundo rustica) in Canada have undergone steep and long-term population declines. Using Breeding Bird Survey data and breeding performance data collected at field sites in three regions across Canada, we examined long- and short-term Barn Swallow population trends in Canada, differences in breeding performance across regions, if average breeding performance measures or colony size predicted regional population growth rates and if local breeding performance is driven by density dependence and/or recruitment. We found that long-term negative population trends were generally stronger in the east and west, and weaker in central Canada. Short-term population trends were generally weakly negative or neutral. Average breeding performance and colony size were poor predictors of regional growth rates observed in the subsequent year. We found little support for density dependence affecting local breeding performance; however, local breeding success, presumably through subsequent recruitment of young, was positively correlated to changes in local colony size in the following year. Since we found juveniles recruited into colonies located in the same region, but no link between average breeding performance and estimated regional population trajectories, our results suggest that extrapolating from local-scale studies to broader populations is challenging, and other demographic rates (i.e., survival) may need to be considered. Overall, our study suggests that contemporary Barn Swallow populations are below carrying capacity in Canada, further suggesting that food limitation is not currently regulating populations. Further study is needed to understand what factors are limiting and regulating Barn Swallow populations in Canada, across the annual cycle.

Agricultural expansion and intensification are some of the leading drivers of biodiversity loss globally. Effective conservation and management strategies for threatened species in agroecosystems require information on how these species are affected by (1) the amount and configuration of natural habitats, and (2) the type and extent of agricultural land covers. The Eastern Whippoor-will (Caprimulgus vociferous) and Common Nighthawk (Chordeiles minor) are two nocturnal aerial insectivores in decline in North America, and have breeding ranges that include agriculturally dominated landscapes. We first assessed mean breeding occupancy of both species in eastern Ontario, Canada in 2016 using acoustic recording units at 127 sites. We then assessed the effects of landscape composition (forest, agriculture, wetlands, and urban covers), forest configuration (mean patch size, number of patches, distance to nearest patch), and agriculture type (perennial forages versus cropland) on Eastern Whip-poor-will occupancy. Eastern Whip-poor-will and Common Nighthawk occupancy in the study area averaged 0.244 and 0.064, respectively. We were unable to examine the relationships between landscape composition/configuration and Common Nighthawk occupancy because of small sample sizes. Nonetheless, Eastern Whip-poor-will occupancy was positively correlated with the amount of wetland cover and forest patch size, was weakly negatively correlated with urban land cover, and was unrelated to the type of agriculture. Our results highlight how the conservation of the Eastern Whip-poor-will in agricultural landscapes of eastern Canada would benefit from both wetland protection and the presence of larger forest patches, which can be accomplished through both forest protection and by allowing forest regeneration on abandoned lands.

ABSTRACT Conservation actions are ongoing for the federally and provincially threatened bobolink ( Dolichonyx oryzivorus ) in Ontario, Canada because of population declines. One conservation action being implemented in agricultural grasslands is the delay of hay harvesting and livestock grazing until 15 July, a general guideline for when bobolink finish breeding. Efficient methods to assess when breeding ceases could benefit bobolink and farmers engaged in conservation by ensuring nesting is finished before agricultural activity occurs and enabling agricultural activity earlier when breeding is finished before 15 July. We conducted field surveys to assess if low‐intensity surveys (i.e., transect surveys, point counts, roadside counts) could accurately detect when bobolink finish breeding compared to intensive monitoring (i.e., spot mapping and nest monitoring). We monitored 29 pastures in 2017 in eastern Ontario and 9 hay fields, 10 restored grasslands, and 6 fallow fields in 2018 in southern Ontario. The date breeding finished varied across fields in 2017 from 13 June to 29 July and in 2018 from 24 June to 30 July, based on spot mapping and nest monitoring. Transect surveys and point counts were good predictors of breeding in a field, as confirmed through spot mapping and nest monitoring, based on generalized linear mixed models. We recommend using transect surveys or point counts as an efficient field method to assess when bobolink finish breeding in a field targeted for bobolink conservation. Our results suggest that 2 consecutive visits that fail to detect evidence of breeding in early July are needed to reasonably infer that breeding has likely finished, leaving a small probability (i.e., <0.01) that breeding may still be occurring. Determining when bobolink finish breeding in fields intended to provide nesting refuges can help maximize conservation benefits and minimize negative effects on agricultural production. © 2020 The Wildlife Society.

Context Agricultural intensification has led to widespread declines in biodiversity. An important component of agricultural intensification in many regions, including eastern Ontario, is the shift from grazing lands and perennial forage crops to annual row crops, with associated increases in use of pesticides. Objectives We predicted that bat abundance and diversity would be lower in sites surrounded by landscapes with more agriculture and where the agriculture was dominated by annual row crops rather than perennial forage crops. Methods We assessed bat occurrence and relative bat abundance with acoustic bat recorders at the centres of 32 landscapes that varied in (1) the proportion of agriculture and (2) the proportion of agriculture that is in annual row crops versus perennial forages (pasture and hay). Results Consistent with our first prediction, the abundance or presence of four bat species, total bat abundance and bat species richness declined with increasing agricultural cover in the surrounding landscape. Inconsistent with our second prediction, the abundance of three bat species, total bat abundance and bat species richness were greatest where the proportion of agriculture in annual crops was about equal to the proportion in perennial forage in the surrounding landscape. Conclusions Based on these results, bat abundance and richness can be increased in agricultural landscapes by reducing the conversion of natural areas to agriculture and by maintaining a balance of perennial forage and annual crop types. We speculate that farmlands with a diversity of crop types provide a more temporally stable supply of insect food for bats.

Studies that have compared biodiversity at organic and conventional farms have generally found that there are more species in greater abundances at organic farms. One widespread problem with previous studies is that most do not control for differences in field structure and landscape composition at organic and conventional farms. Thus, the effects observed may be due to factors other than organic farming practices. We addressed this problem by selecting matched organic-conventional pairs of soybean fields such that in each pair the soybean fields were similar in size, hedgerow length, and surrounding landscape composition within 1 km, 2 km and 3 km of the fields. At each of our 16 field pairs (32 sites), we measured relative differences in bat species richness and abundance using acoustic bat recorders, and bat prey availability using black-light traps. We predicted that organic soybean fields would have greater bat species richness, bat abundance and bat prey abundance than conventional soybean fields due to the prohibition of synthetic pesticides and longer more diverse crop rotations in organic fields, both of which should benefit bat insect prey. We found that organic soybean fields had higher bat species richness, bat abundance and bat prey abundance than conventional fields, after controlling for the effect of differences in soybean height between conventional and organic fields. Our results suggest that the management practices used at organic farms benefit bats at least in part by providing greater bat prey availability.

We describe an interspecific relationship wherein grizzly bears (Ursus arctos horribilis) appear to seek out and consume agricultural seeds concentrated in the middens of red squirrels (Tamiasciurus hudsonicus), which had collected and cached spilled grain from a railway. We studied this interaction by estimating squirrel density, midden density and contents, and bear activity along paired transects that were near (within 50 m) or far (200 m) from the railway. Relative to far ones, near transects had 2.4 times more squirrel sightings, but similar numbers of squirrel middens. Among 15 middens in which agricultural products were found, 14 were near the rail and 4 subsequently exhibited evidence of bear digging. Remote cameras confirmed the presence of squirrels on the rail and bears excavating middens. We speculate that obtaining grain from squirrel middens encourages bears to seek grain on the railway, potentially contributing to their rising risk of collisions with trains.

Some ways that agricultural areas have intensified, include increased agro-chemical inputs, use of annual row crops and agricultural extent. These changes would be expected to reduce insect prey for bats, causing smaller bat populations to be supported. Chapter 1 examines the influence that the proportion of the landscape in agriculture and the proportion of agricultural lands in annual crops (vs. perennial forage crops) has on relative bat abundance and diversity. We found that bat abundance was highest in landscapes that had a low proportion of agriculture and where the proportion of agriculture in annual crops was about equal to the proportion in perennial forage. Chapter 2 examines the influence of organic versus conventional farming practices using match-organic conventional soybean field pairs on bat diversity, bat abundance and bat prey abundance. We found organic fields had higher bat diversity, bat abundance and bat prey abundance than conventional fields.