Peregrine Falcons Nest Successfully During Reconstruction of Bridge Over Ohio River

Peregrine falcons (Falco peregrinus) often nest on bridges over rivers and other waterways, resulting in the need for mitigation planning for bridge maintenance and reconstruction. However, mitigation guidelines for peregrine falcon nests during bridge reconstruction are lacking in the literature. In this paper, we describe the monitoring, spatial, and temporal buffers, nest box installation, and other methods that allowed peregrine falcons to nest successfully on the Milton-Madison (US-421) Bridge during demolition and reconstruction. Construction activities occurred over a 4-year period (2011–2014), and coordination with local road departments and contracted engineers was necessary to accommodate the falcon nest. Nonetheless, construction activities were able to progress without causing major construction expense or delays, and the nesting falcons were able to fledge 14 young during the project

Tradeoffs May Counteract Effects of Telecommunication Towers on Osprey Nesting

The number of telecommunication towers (TCTs) throughout the United States has and continues to increase exponentially. Increased TCT placement has been implicated in local population increases in platform nesting birds such as ospreys (Pandion haliaetus). However, osprey use of artificial structures can cause conflicts with humans because of economic costs and risks to human safety. Managers require better information regarding the effect of artificial nesting surfaces, such as TCTS, on osprey reproduction to make informed decisions regarding species conservation and to mitigate potential conflicts. The objective of our study was to evaluate the influence of TCTs on osprey productivity and adult nesting behaviors. From March to July 2019, we monitored 30 osprey nests located in western Kentucky, USA, on TCTs (n = 11), navigation channel markers (NCMs; n = 10), and natural surfaces (NATs; n = 9). We found no differences in nest success, productivity, or the proportion of male ospreys perched at the nest between surface types. Nests on NCMs received 1.9–2.1 times more fish than nests on NATs and TCTs, respectively. Moreover, NCMs experienced 5.4–8.0 times more disturbances per hour compared to NATs and TCTs, respectively. Our data suggest ospreys nesting on TCTs are productive contributors to local populations. We recommend deterrence of osprey nesting should be focused on locations that are unsafe for ospreys and/or pose insurmountable problems for communication infrastructure

Anticoagulant rodenticide exposure and toxicosis in bald eagles (Haliaeetus leucocephalus) and golden eagles (Aquila chrysaetos) in the United States

Raptors, including eagles, are geographically widespread and sit atop the food chain, thereby serving an important role in maintaining ecosystem balance. After facing population declines associated with exposure to organochlorine insecticides such as dichlorodiphenyltrichloroethane (DDT), bald eagles (Haliaeetus leucocephalus) have recovered from the brink of extinction. However, both bald and golden eagles (Aquila chrysaetos) are exposed to a variety of other toxic compounds in the environment that could have population impacts. Few studies have focused on anticoagulant rodenticide (AR) exposure in eagles. Therefore, the purpose of this study was to determine the types of ARs that eagles are exposed to in the USA and better define the extent of toxicosis (i.e., fatal illness due to compound exposure). Diagnostic case records from bald and golden eagles submitted to the Southeastern Cooperative Wildlife Disease Study (University of Georgia) 2014 through 2018 were reviewed. Overall, 303 eagles were examined, and the livers from 116 bald eagles and 17 golden eagles were tested for ARs. The percentage of AR exposure (i.e., detectable levels but not associated with mortality) in eagles was high; ARs were detected in 109 (82%) eagles, including 96 (83%) bald eagles and 13 (77%) golden eagles. Anticoagulant rodenticide toxicosis was determined to be the cause of mortality in 12 (4%) of the 303 eagles examined, including 11 bald eagles and 1 golden eagle. Six different AR compounds were detected in these eagles, with brodifacoum and bromadiolone most frequently detected (81% and 25% of eagles tested, respectively). These results suggest that some ARs, most notably brodifacoum, are widespread in the environment and are commonly consumed by eagles. This highlights the need for research to understand the pathways of AR exposure in eagles, which may help inform policy and regulatory actions to mitigate AR exposure risk