Understanding animal mating systems is an important component of their conservation, yet the precise mating times for many species of bats are unknown. The aim of this study was to better understand the details and timing of reproductive events in species of bats that die most frequently at wind turbines in North America, because such information can help inform conservation strategies. We examined the reproductive anatomy of hoary bats (Lasiurus cinereus), eastern red bats (L. borealis), and silver-haired bats (Lasionycteris noctivagans) found dead beneath industrial-scale wind turbines to learn more about when they mate. We evaluated 103 L. cinereus, 18 L. borealis, and 47 Ln. noctivagans from wind energy facilities in the United States and Canada. Histological analysis revealed that most male L. cinereus and L. borealis, as well as over half the Ln. noctivagans examined had sperm in the caudae epididymides by late August, indicating readiness to mate. Testes regression in male hoary bats coincided with enlargement of seminal vesicles and apparent growth of keratinized spines on the glans penis. Seasonality of these processes also suggests that mating could occur during August in L. cinereus. Spermatozoa were found in the uterus of an adult female hoary bat collected in September, but not in any other females. Ovaries of all females sampled had growing secondary or tertiary follicles, indicating sexual maturity even in first-year females. Lasiurus cinereus, L. borealis, and Ln. noctivagans are the only North American temperate bats in which most first-year young of both sexes are known to sexually mature in their first autumn. Our findings provide the first detailed information published on the seasonal timing of mating readiness in these species most affected by wind turbines.

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Thermocron iButton dataloggers are widely used to measure thermal microclimates experienced by wild animals. The iBBat is a smaller version of the datalogger, also commercially available, that is used to measure animal skin or core body temperatures when attached externally or surgically implanted. Field observations of bats roosting under a bridge suggested that bats avoided locations with iButtons. A heterodyne bat detector revealed that the dataloggers emitted ultrasound which was detectable from a distance of up to 30 cm. We therefore recorded and quantified the acoustic properties [carrier frequency (Hz) and root mean square sound pressure level (dB SPL)] of iButton and iBBat dataloggers. All units emitted a 32.9 kHz pure tone that was readily picked up with a time expansion bat detector at a distance of 1 cm, and most were detected at a distance of 15 cm. The maximum amplitude of iButton dataloggers was 46.5 dB SPL at 1.0 cm-a level within the range of auditory sensitivity for most small mammals. Wrapping iButtons in plastic insulation severely attenuated the amplitude of ultrasound. Although there was a statistically significant reduction in rates of warming and cooling with insulation, this effect was small and we suggest that insulation may be a viable solution to eliminate unwanted ultrasonic noise in instances when small delays in thermal response dynamics are not a concern. We recommend behavioural studies to assess if the electronic signals emitted by iButtons are disturbing to small mammals.

According to the island syndrome and island rule hypotheses, island isolation and reduced area lead to phenotypic shifts in ecologically relevant traits in insular populations compared to mainland ones. These hypotheses have been built up with oceanic islands in mind or islands where isolation is high and colonization rate relatively limited. This set of hypotheses, however, may not be applicable to other inland–island systems or recently fragmented landscapes. We investigated how island life leads to phenotypic changes in two rodent metapopulations: deer mice and red‐backed voles in a fragmented system on a river in Canada. From 2013 to 2016, we sampled 454 deer mice and 665 red‐backed voles spread across 10 islands and six mainland sites on river shores. We compared body mass, tail and hindfoot length, exploration and reaction towards predators, between individuals from island and mainland sites, and assessed the role of connectivity, isolation and area of islands. Insular individuals from both species were less aggressive towards potential predators and insular mice were more thorough explorers compared to mainland ones. Male mice were heavier and juvenile mice had longer tails on islands. However, contrary to expectations, we found negative relationships between aggressiveness and juvenile exploration score with patch connectivity for mice. Island connectivity significantly affected tail length of mice through a concave relationship. Finally, vole aggressiveness and exploration of male mice were positively correlated to island isolation. Our study supports only partially the predictions of the island syndrome hypothesis. It provides empirical evidence that inland–island life can modify traits in deer mice, but less so in red‐backed voles in a non‐oceanic system. It also raises questions about the direct causal factors of these changes in a naturally fragmented landscape, and urges for more predictive models about phenotypic/genetic divergence among populations in natural and artificial fragmented landscapes.