Hareport hazard: Identifying hare activity patterns and increased mammal–aircraft strike risk at an International Airport

Abstract

Reported strike events between wildlife and aircraft are hazardous to aircraft and airfield operations and are increasing globally. To develop effective mitigation strategies, the relative hazard a species poses to aircraft, as well as information relating to its life history, are key to the development of effective mitigation strategies in Wildlife Hazard Management Plans. However, given the complex nature of airfield environments with access restrictions and the presence of sensitive equipment, the collection of high‐quality ecological data can be difficult. Here we use motion‐activated camera traps to collect activity data on a population of Irish hares (Lepus timidus hibernicus) inhabiting the airfield at Dublin International Airport, to investigate the link between hare activity and aircraft activity in relation to hare strikes. Camera traps revealed that the hare population at the airfield largely displayed a bimodal crepuscular activity pattern, with activity peaking at sunrise and at sunset. Recorded hare strike times at the airfield were closely associated with hare activity times with a high temporal overlap between these datasets. In comparison, hare activity and aircraft movement activity had a moderate overlap across all seasons, with strikes peaking at times with low aircraft movements. We demonstrate the importance of understanding the circadian and seasonal activity patterns of hazardous species at airfields for targeted strike mitigation.

Dublin Hareport: The movement ecology and airfield interactions of resident, airside hares, at an international airport

“…Identifying patterns as to when high‐risk species are entering tarmacked areas is essential to the development of strike mitigation measures on both a seasonal and temporal scale. Tarmacked area interactions occurred during the current study according to a bimodal, crepuscular pattern, similar to activity patterns previously recorded for Irish hares (Caravaggi et al., 2018) and indeed, for this specific population (camera trap data; Ball et al., 2022). We found cumulative movement and the number of tarmacked airfield interactions to be highest during the Spring sampling period.…”

“…Hares generally exhibit a bimodal, crepuscular activity pattern (Caravaggi et al., 2018; Pettigrew et al., 2021), and this has also been recorded for this specific population (Ball et al., 2022). However, day length in Ireland varies substantially with the seasons, with the longest days in the summer recording ~17 h of daylight and the shortest days in winter ~7 h. Therefore, understanding how tarmacked area interactions vary with the rising/setting of the sun could have important management implications.…”

“…However, with the majority of interactions from these data having been recorded with semi‐operational or inactive areas (runways 16–34 and 10L‐28R, respectively), it is uncertain how frequently hares would interact with tarmacked areas with frequent aircraft movements. At Dublin Airport, aircraft movements increase from c.06:00 and remain constant for the duration of the day, before dropping off approaching midnight (00:00; Ball et al., 2022).…”

“…com), depending on when the interaction event occurred. All tarmacked area interactions, which occurred between the hours of 00:00 and 11:59 were offset relative to sunrise, and all events that occurred between 12:00 and 23:59 were offset relative to sunset (as per Caravaggi et al (2018) & Ball et al (2022). All events which occurred between sunrise and sunset were converted to positive integers to indicate hours of daylight and all events which occurred between the hours of sunset and sunrise were converted to negative integers to indicate hours of darkness.…”

“…The complex nature of airfield environments, coupled with the elusive nature of many mammal species, can make the collection of high-quality ecological data complicated. Hence, researchers often rely on remote sensing methods, such as camera traps (Ball et al, 2022;Carswell et al, 2021). While GPS transmitters have been used to study the movements of large waders (Anatidae) in proximity to airfields (Askren et al, 2019;Lehrke et al, 2017), here we present the first known study to track the movements of a terrestrial mammal, the Irish hare (Lepus timidus hibernicus), within an airfield environment.…”