The habitat connectivity hypothesis of escape in urban woodland birds

Abstract

Habitat destruction and fragmentation increasingly bring humans into close proximity with wildlife, particularly in urban contexts. Animals respond to humans using nuanced anti-predator responses, especially escape, with responses influenced by behavioral and life history traits, the nature of the risk, and aspects of the surrounding environment. Although many studies examine associations between broad-scale habitat characteristics (i.e., habitat type) and escape response, few investigate the influence of fine-scale aspects of the local habitat within which escape occurs. We test the “habitat connectivity hypothesis,” suggesting that given the higher cost of escape within less connected habitats (due to the lack of protective cover), woodland birds should delay escape (tolerate more risk) than when in more connected habitat. We analyze flight-initiation distances (FIDs) of five species of woodland birds in urban Melbourne, south-eastern Australia. A negative effect of habitat connectivity (the proportion of the escape route with shrubs/trees/perchable infrastructure) on distance fled was evident for all study species, suggesting a higher cost of escape associated with lower connectivity. FID did not vary with connectivity at the location at which escape was initiated (four species), apart from a positive effect of habitat connectivity on FID for Noisy Miner Manorina melanocephala. We provide some support for two predictions of the “habitat connectivity hypothesis” in at least some taxa, and conclude it warrants further investigation across a broader range of taxa inhabiting contrasting landscapes. Increasing habitat connectivity within urban landscapes may reduce escape stress experienced by urban birds.

Adaptive Flight Strategies in Urban Birds: Unraveling the Intricacies between Flight Initiation Distance and Distances Fled

“…In contrast, the life history trade-offs component claims that birds exhibiting longer FID tend to display a higher tendency towards avoidance of risk, prioritizing survival over other aspects of their life history, such as reproduction. The claim is supported by studies suggesting that individuals with longer FID have a lower tendency to engage in risky behaviors and increased survival rates of adults (Møller 2014;Radvan et al 2023). Overall, the longer FID observed in birds with longer distances ed can be attributed to fear and the trade-offs associated with survival and reproduction.…”

Leash Status of Approaching Dogs Mediates Escape Modality but Not Flight-Initiation Distance in a Common Urban Bird

“…We describe a cost to magpie-larks of unleashed dogs that extends beyond obvious chasing and harassment [23]. Fear of a small, unleashed dog evoked more intense, energetically demanding, and spatially disruptive escape responses than fear of a leashed dog (see [14,29]). The dog itself did not bark or roam, which might trigger avian escape responses [23,39].…”

“…Urban birds live in a human-and dog-rich environment and, as such, must respond to people and their dogs (which can alter their normal states, i.e., cause disturbance) [12]. Urban birds may be less responsive to humans [13], but responses persist in urban parks [14][15][16].…”

Urban noise slows down the antipredator reaction of Eurasian Magpies

“…Since all data was collected in Prague, we can assume a similar predation risk across the collected data. Additionally, the site (or park) was used as a random factor to reduce confounding variables (such as the variability among human activity in different sites and the type of vegetation cover), which may impact the antipredator behavior (Radvan et al, 2023).…”