Changes in Detected Anticoagulant Rodenticide Exposure in Barn Owls ( Tyto alba) in Kentucky, USA, in 2012-16.

Anticoagulant rodenticides (ARs) are widely used across North America to control rodent infestations but may cause direct mortality or nonlethal effects when secondarily consumed by raptors. Barn Owls ( Tyto alba) are at high risk for secondary consumption because they specialize in rodent prey and often live in human-made structures. We investigated the exposure of Barn Owls in Kentucky, US, to ARs and to dicoumarol, an anticoagulant compound naturally found in certain moldy forages. We tested the liver tissue of 48 Barn Owl carcasses collected during 2012-16. We confirmed exposure to one or more ARs in 33% of the birds examined and detected dicoumarol in 13% of the samples. Rodenticides detected included brodifacoum, coumachlor, and bromadiolone. The prevalence of detected exposure to brodifacoum for after-hatch-year birds (65%) was significantly ( P=0.012) higher than hatch-year birds (22%). Brodifacoum was the most commonly detected AR, found in 88% of AR-positive birds. The pesticide registration for this chemical in the US was canceled in 2015 for general consumer products, which likely resulted in a decreasing rate of detected exposure to brodifacoum during our study. We present these results as an example of secondary exposure rates during a period when a pesticide has been restricted and then removed from the consumer market.

Maxent-directed field surveys identify new populations of narrowly endemic habitat specialists.

BACKGROUND: Rare or narrowly endemic organisms are difficult to monitor and conserve when their total distribution and habitat preferences are incompletely known. One method employed in determining distributions of these organisms is species distribution modeling (SDM). METHODS: Using two species of narrowly endemic burrowing crayfish species as our study organisms, we sought to ground validate Maxent, a commonly used program to conduct SDMs. We used fine scale (30 m) resolution rasters of pertinent habitat variables collected from historical museum records in 2014. We then ground validated the Maxent model in 2015 by randomly and equally sampling the output from the model. RESULTS: The Maxent models for both species of crayfish showed positive relationships between predicted relative occurrence rate and crayfish burrow abundance in both a Receiver Operating Characteristic and generalized linear model approach. The ground validation of Maxent led us to new populations and range extensions of both species of crayfish. DISCUSSION: We conclude that Maxent is a suitable tool for the discovery of new populations of narrowly endemic, rare habitat specialists and our technique may be used for other rare, endemic organisms.

A new species of crayfish in the genus Orconectes (Decapoda: Cambaridae) from the Tennessee River Drainage with comments on and key to members of the O. juvenilis Species Complex.

The crayfish subgenus Procericambarus (genus Orconectes) found in the Eastern Highlands of the United States represents a rich assemblage of stream-dwelling macroinvertebrates. While the taxonomic status and distribution of its members were clarified in a previous study, newly diagnosed characters and newly collected specimens warranted a revision to previous hypotheses of Procericambarus membership in the southeastern United States. Using morphological characters, we describe herein a new species of crayfish occurring in the Tennessee River drainage of northern Alabama and southwestern Tennessee. We also provide a revised key for the identification of members of O. juvenilis Species Complex.