Out of sight, out of mind? Testing the effects of overwinter habitat alterations on breeding territories of a migratory endangered species

Abstract

Anthropogenic activities are one of the main threats to species living in humandominated landscapes and can promote behavioral changes in birds. This paper presents a novel approach to test how a migratory species responds to habitat alterations occurring in nesting territories during winter, when the species is absent. From 2000 to 2016, we collated territory and nest monitoring data for the endangered Egyptian Vulture Neophron percnopterus in the north of Spain, to test the effects of overwinter habitat alterations (OHA) around breeding territories on the species reproductive output. We monitored 70 different nest sites and observed OHA around the nesting area in 39 cases. Probability of switching to another nesting site almost tripled after OHA. Pairs that switched experienced substantially decreased breeding success and avoided reusing the nest for 4.8 AE 4.64 years. The presence of determinate landscape elements that provide screening, such as forest patches, increased nest reoccupancy probability after OHA by more than 0.3, to 0. 55 (compared to 0.24 when no screening was present). We also found that the distance and the situation of the OHA were critical factors explaining reproduction probabilities at nest sites. Our results demonstrate how OHA can strongly impact the breeding behavior of long-lived species. This highlights the need to examine the long-term impact of OHA rather than focusing only on disturbances during sensitive periods, as is often the case with habitual mitigation measures.

The Distribution, Nesting Habits and Status of Threatened Vulture Species in Protected Areas of Central India

“…Human disturbance has been recognized as a prominent factor for vulture territory abandonment (Carrete et al, 2007;Zuberogoitia et al, 2014;Kruger et al, 2015). It can impact them directly (e.g., by persecution and harvesting) or indirectly, via effects on the quantity, quality, or configuration of the landscape and consequently on the habitats that it contains (Hollander et al, 2011;Kamp et al, 2016;Morant et al, 2018). While some authors suggest that vultures (Egyptian Vulture) are tolerant to human activities (Ceballos & Donazar, 1989), human disturbance would lead raptors (including old world vulture) to abandoning their nests and thereby reducing breeding success (Chomba & Simuko, 2013).…”

Management Actions Promote Human-Wildlife Coexistence in Highly Anthropized Landscapes: The Case of an Endangered Avian Scavenger

“…According to their duration and frequency, disturbances were classified into: (1) low: low level, specific, non-recurring disturbances (i.e., occasionally detected and did not cause an evident alert behavior and did not alter the normal reproductive behavior of the Egyptian vultures; e.g., people practicing sports or forestry and farming works for short periods (less than 1 or 2 h) and far from the nest site (>600 m, considering the 1 km radius); (2) medium: one-off high level or medium-level disturbances (i.e., when disturbance duration extended for several hours; e.g., multitudinous races during one whole day, large vehicles, or machines working for several hours); and (3) high: chronic and high-level disturbances (i.e., detected through all day, or during several days, or when the effect was permanent; e.g., forestry activities, works related to the construction of new infrastructures and actions which produced direct disturbance, permanent alert behavior of the adults and negative changes in the expected rate of reproductive parameters, during the entire activity period). High-level disturbances can carry on temporal (e.g., machines and vehicles working) or permanent habitat changes (e.g., opening of new roads, trails and paths close to nests, or forest cuts which eliminate protection patches of vegetation around the nests) and, consequently, they can influence nesting in the future (Morant et al, 2018). Further, considerable modification of areas surrounding nesting sites (permanent habitat changes), even if they take place during the winter -when breeders are absent from the area-, can push adults to move to alternative, less preferred or lower quality sites, resulting in higher chances of failure in subsequent nesting events (Morant et al, 2018).…”

“…High-level disturbances can carry on temporal (e.g., machines and vehicles working) or permanent habitat changes (e.g., opening of new roads, trails and paths close to nests, or forest cuts which eliminate protection patches of vegetation around the nests) and, consequently, they can influence nesting in the future (Morant et al, 2018). Further, considerable modification of areas surrounding nesting sites (permanent habitat changes), even if they take place during the winter -when breeders are absent from the area-, can push adults to move to alternative, less preferred or lower quality sites, resulting in higher chances of failure in subsequent nesting events (Morant et al, 2018).…”

“…Annually, before the arrival of this migratory species from Africa to the study area, the first management measure consisted of preventing habitat alterations within 1 km of each of the 86 nest sites. Human activities that could potentially modify landscape and vegetation around nest sites (e.g., opening tracks or falling timber plots; see Morant et al, 2018 for details on such activities) must be approved by BCC environmental managers following the basis for the species protection.…”

“…Breeding pairs arrive from their winter grounds in Africa in late February and early March and remain in their territories until mid-September/October (Phipps et al, 2019). They generally reuse the same nest unless they are disturbed during sensitive phases, or the nest area is altered (Zuberogoitia et al, 2008;Morant et al, 2018).…”