The reproductive success of sandhill cranes in midwestern landscapes

Abstract

A number of wildlife species have recovered from the brink of extinction to flourish and, in some cases, even become a commonly recognized urban species (e.g., Canada goose [Branta canadensis]). Broadly extirpated from much of their historical range in North America, the sandhill crane (Antigone canadensis) demonstrated this potential for population recovery. The trajectory of the eastern population of greater sandhill cranes is remarkable—perhaps as many as 90,000 cranes now occur throughout the same Great Lakes states that reported only dozens of birds less than a century ago. However, understanding future population growth of the species remains uncertain because breeding birds are increasingly exposed to the pressures of urban sprawl and a changing agricultural landscape. From 2009 to 2014 we investigated the survival of sandhill crane nests and young up to 11 weeks of age (the point at which they are capable of flight) in the core of the eastern population's range in central Wisconsin and at its peripheral extent in a rapidly developing urban region of northeastern Illinois, USA. We located crane nests via systematic surveys on foot and from helicopters, we then radio‐tagged the young and monitored them until they died or were capable to sustained flight. Overall, young were more likely to hatch from nests in Illinois (60%) than in central Wisconsin (46%), regardless of differences in land cover surrounding the nest site. In contrast, the survivorship of young was positively correlated with urban land cover in both regions but higher in central Wisconsin (54%) than in northeast Illinois (27%). Overall, the probability of producing young was greater in landscapes with more urban development, regardless of region. We suggest that differences in predator composition, predator behavior, and crane density between rural and urban areas is the primary reason for the difference in crane productivity. Higher recruitment of sandhill cranes using urban landscapes may allow cranes to echo the population trajectory of urban Canada geese. We anticipate that sandhill cranes will continue to use urban landscapes, and likely expand their geographic range as breeding pairs benefit from the increased survivorship of young in those landscapes. © The Wildlife Society, 2019

Drones as a tool to study and monitor endangered Grey Crowned Cranes (Balearica regulorum): Behavioural responses and recommended guidelines

“…Their decline is primarily attributed to habitat loss (Amulike et al., 2020 ; Austin et al., 2018 ; Harris & Mirande, 2013 ) with numerous species struggling to obtain successful breeding outcomes as a result of breeding site loss or degradation (e.g., Fakarayi et al., 2016 ; Su & Zou, 2012 ). Yet, other crane species have shown greater resilience and noticeable population growth following increased foraging opportunities in agricultural landscapes (e.g., Fox et al., 2019 ; Hemminger et al., 2022 ; Lacy et al., 2015 ; van Velden et al., 2017 ). While the revival of these populations can be seen as a success, an increased dependence of cranes on croplands has also led to a conflict between farmers and cranes, presenting its own set of challenges (Austin et al., 2018 ; Hemminger et al., 2022 ; Nilsson et al., 2019 ; van Niekerk, 2018 ).…”

Breeding expansion of sandhill cranes in Quebec

“…mosaics of agricultural fields, wetlands, and urban areas(Van Horn et al 2010, Lacy et al 2015, Fox et al 2019), which increases feeding opportunities. We had hypothesized (H2) that the cover of these land cover types in each cell facilitates the colonization by the bird(Van Horn et al 2010, Lacy et al 2015.…”