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Scouts vs Usurpers: Alternative foraging strategies facilitate coexistence between Neotropical Cathartid Vultures
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  • Christopher Beirne,
  • Mark Thomas,
  • Arianna Bastoe,
  • Eleanor Flatt,
  • Giancarlo Inga Diaz,
  • Diego Rolim Chulla,
  • Flor Perez Mullisaca,
  • Rosio Vega Quispe,
  • Caleb Quispe Quispe,
  • Adrian Forsyth,
  • Andrew Whitworth
Christopher Beirne
Osa Conservation
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Mark Thomas
Osa Conservation
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Arianna Bastoe
Osa Conservation
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Eleanor Flatt
Osa Conservation
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Giancarlo Inga Diaz
Osa Conservation
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Diego Rolim Chulla
Osa Conservation
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Flor Perez Mullisaca
Osa Conservation
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Rosio Vega Quispe
Osa Conservation
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Caleb Quispe Quispe
Osa Conservation
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Adrian Forsyth
Osa Conservation
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Andrew Whitworth
Osa Conservation

Corresponding Author:[email protected]

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Abstract

1. Understanding how diverse assemblages of scavengers can coexist on shared ecological resources is a fundamental challenge in community ecology. However, current approaches typically focus on behaviour at carcass provisioning sites, missing how important differences in movement behaviour and foraging strategies can facilitate sympatric species coexistence. Such information is particularly important for vultures - obligate scavengers representing the most endangered avian foraging guild. Their loss from ecosystems can trigger trophic cascades, mesopredator release, and disease outbreaks. 2. We use a combination of morphometric measurements and movement data from wild King (Sarcoramphus papa) and Greater yellow-headed (Cathartes melambrotus) vultures, coupled with carcass visitation data from animal carcass provisioning experiments to characterise scavenger community structure and strategies in the Peruvian Amazon. 3. King vulture body mass and tarsi length were larger (43% and 45% respectively), and tail shorter (22%) than the Greater-yellow headed vulture. King vultures also had substantially larger home ranges (~500%), flew higher than Greater yellow headed vultures (695m vs. 360 m), and despite flying similar distances each day, were active later in the day. At carcasses, Greater-yellow headed vultures typically arrived first, but were rapidly outnumbered by both King and Black vultures (Coragyps atratus). 4. We find that the movement behaviour of obligate apex scavengers in the western Amazon is linked to their ability to coexist - the Greater -yellow headed vultures, a smaller stature ‘scouting’ species adapted to fly low and forage early, arrive first, but are ultimately displaced by larger-bodied king vultures at large ephemeral carrion resources. Expansion of future GPS tracking initiatives should facilitate the exploration of direct facultative interactions from animal movement data and give further insight into how diverse communities assemble and interact.
25 Apr 2024Published in Ibis. https://doi.org/10.1111/ibi.13327