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Intra-seasonal changes in depredation influence nest survival, but this may be mediated by the foraging behavior of predators or seasonal variability in habitat features. Intra-seasonal differences in factors influencing daily nest survival rates of Black Terns (Chlidonias niger) were studied in southern Ontario, Canada, during May-August 2015 and 2016. Survival of early and late-nesting individuals in relation to nest-specific temporal and spatial characteristics was investigated, including nest habitat change over the nesting cycle. The daily nest survival rate for early nesters (n = 112) declined with increasing nest age (β = -14.97; P = < 0.001), and rose with increased proportion of vegetation (β = 0.01; P = 0.02) and increased conspecific nest spacing (β = 0.01; P = 0.04). Daily nest survival rate for late nesters (n = 80) was influenced by increasing nest age (β = -12.99; P = < 0.001), with a decline during the nestling stage, and no habitat or spatial correlates. A propensity toward smaller clutch sizes with diminished survival in the late season (β = 0.67; P = 0.01) further highlights intra-seasonal differences in factors that affect survival. Predator foraging behavior may influence intra-seasonal survival patterns more than seasonal variability in habitat features. [ABSTRACT FROM AUTHOR]

Recovery strategies for species at risk have been criticized for a lack of specificity (i.e. measurable and quantifiable criteria) as well as for taxonomic biases, both of which may ultimately affect species’ recovery. However, it is unknown whether the clarity and specificity of written statements within recovery strategies can also influence recovery efforts for certain species at risk. To assess this we examined the variation in semantic uncertainty in the target statements of recovery strategies for Canadian species at risk at the federal and provincial levels. We quantified the lexical density and readability of recovery target statements and examined them for differences according to taxonomic grouping, jurisdiction and degree of endangerment. Recovery statements for the category threatened species had greater semantic uncertainty than those for higher (endangered) and lower (special concern) categories, which is likely to be a function of the fact that threatened species are less abundant than special concern species but are subject to greater errors in population estimates than endangered species. We also found that recovery statements for non-charismatic species (e.g. plants and invertebrates) had greater semantic uncertainty than those for other taxa, which may be related to the resources available for studying and conserving them. Our results suggest a need for greater specificity in recovery targets for threatened and non-charismatic species, and that more focused data collection on these species’ populations is warranted. [ABSTRACT FROM AUTHOR]

Abstract: The breeding phenology of three grassland bird species was studied in managed hayfields of Nova Scotia, Canada: bobolink (Dolichonyx oryzivorus), savannah sparrow (Passerculus sandwichensis), and Nelson''s sharp-tailed sparrow (Ammodramus nelsoni subvirgatus), under delayed hay cutting regimes (post-1 July). Weekly changes were monitored in several measures of hay nutritional quality (percent crude protein (CP %), acid detergent fibre (ADF), calcium (Ca) and phosphorus (P)). Timing of peak fledging was variable across years, but generally occurred in the first week of July. Delay of cutting by 1 week in late June or early July resulted in a small reduction in hay nutritional quality. However, that hay would still meet energy and CP % requirements for non-lactating beef cows. Regression models showed that a delay of 1.5 weeks (from 20 June to 1 July) in cutting translated to a mean decrease in CP % of 2.1. Conversely, this delay secured an increase in the rate of fledgling, from 0 to 20% for bobolink, 56% for savannah sparrow, and 44% for Nelson''s sharp-tailed sparrow. Postponing cut by 1 more week (to a minimum of 7 July) gave the benefit of allowing maximum fledging rates for all species, while CP % lost 3.5. While this level of CP % is unlikely to support high maintenance periparturient cows and feeder/finisher cattle, it could be made profitable through mineral supplementation. ADF levels were considerably elevated, while Ca and P improved in the same time period. These trends show delayed hay cutting can be a viable option for farmers opting to conserve breeding birds on hayfields. The feasibility of delaying cut varies with a farm''s specialization, and to a degree, breed kept. Such practices can be incorporated into a holistic approach to agroecosystem management. [Copyright &y& Elsevier]

Presents a study which examined the summer behavior of non-breeding and failed breeding Common Loon, or Gavia immer, from lakes in Canada. Background on the bredding behavior of common loon; Method; Findings.

Elucidating the adaptive genetic potential of wildlife populations to environmental selective pressures is fundamental for species conservation. Genes of the major histocompatibility complex (MHC) are highly polymorphic, and play a key role in the adaptive immune response against pathogens. MHC polymorphism has been linked to balancing selection or heterogeneous selection promoting local adaptation. However, spatial patterns of MHC polymorphism are also influenced by gene flow and drift. Wolverines are highly vagile, inhabiting varied ecoregions that include boreal forest, taiga, tundra, and high alpine ecosystems. Here, we investigated the immunogenetic variation of wolverines in Canada as a surrogate for identifying local adaptation by contrasting the genetic structure at MHC relative to the structure at 11 neutral microsatellites to account for gene flow and drift. Evidence of historical positive selection was detected at MHC using maximum likelihood codon-based methods. Bayesian and multivariate cluster analyses revealed weaker population genetic differentiation at MHC relative to the increasing microsatellite genetic structure towards the eastern wolverine distribution. Mantel correlations of MHC against geographical distances showed no pattern of isolation by distance (IBD: r = -0.03, p = 0.9), whereas for microsatellites we found a relatively strong and significant IBD (r = 0.54, p = 0.01). Moreover, we found a significant correlation between microsatellite allelic richness and the mean number of MHC alleles, but we did not observe low MHC diversity in small populations. Overall these results suggest that MHC polymorphism has been influenced primarily by balancing selection and to a lesser extent by neutral processes such as genetic drift, with no clear evidence for local adaptation. This study contributes to our understanding of how vulnerable populations of wolverines may respond to selective pressures across their range.