Predation in Ground-Nesting Birds: an Experimental Study Using Natural Egg-Color Variation
We tested the hypothesis that cryptically colored eggs would suffer less predation than conspicuous eggs in the ground-nesting red-legged partridge, Alectoris rufa. We used A. rufa as a model species because it has a wide range of natural egg colors, the eggs are widely available from breeding farms...
| Main Authors: | , , , |
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| Format: | Article |
| Language: | English |
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Resilience Alliance
2007-06-01
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| Series: | Avian Conservation and Ecology |
| Subjects: | |
| Online Access: | http://www.ace-eco.org/vol2/iss1/art2/ |
| _version_ | 1797969529431654400 |
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| author | Aurora M. Castilla André A. Dhondt Ramón Díaz-Uriarte David Westmoreland |
| author_facet | Aurora M. Castilla André A. Dhondt Ramón Díaz-Uriarte David Westmoreland |
| author_sort | Aurora M. Castilla |
| collection | DOAJ |
| description | We tested the hypothesis that cryptically colored eggs would suffer less predation than conspicuous eggs in the ground-nesting red-legged partridge, Alectoris rufa. We used A. rufa as a model species because it has a wide range of natural egg colors, the eggs are widely available from breeding farms, and nests are easily mimicked because they are scrapes containing no vegetation. The study was conducted in the spring of 2001 in forest and fallow fields of central Spain in Castilla La Mancha, Ciudad Real. We used 384 clutches of natural eggs that were white, white spotted, brown, or brown spotted. Within clutches, eggs were consistent in color and size; among clutches, color differences were distributed across habitats. Clutches were checked once after 2 wk of exposure. Cryptic coloration had a survival advantage that was dependent on the local suite of predators. Rodent predation was nonselective with respect to clutch color; however, avian predation was significantly higher for conspicuous clutches. In addition, there was an interaction of landscape and egg color for avian predation. In forest landscapes, the clutches with highest survival were brown spotted, whereas in fallow landscapes, brown and brown spotted clutches had higher survival than white and white potted clutches. Thus, both the predator suite and the landscape had significant effects on the value of cryptic egg coloration. Our study is relevant for conservationists and managers in charge of restocking programs in hunting areas. The release of other partridge species or their hybrids could result in hybridization with wild partridges, potentially leading to nonoptimal clutch pigmentation and reduced survival of the native species. We therefore recommend that local authorities, managers, and conservationists be cautious with the use of alien species and hybrids and release only autochthonous species of partridges within their natural ranges. |
| first_indexed | 2024-04-11T03:03:39Z |
| format | Article |
| id | doaj.art-294480e0525a43448256956c81d7ddf0 |
| institution | Directory Open Access Journal |
| issn | 1712-6568 |
| language | English |
| last_indexed | 2024-04-11T03:03:39Z |
| publishDate | 2007-06-01 |
| publisher | Resilience Alliance |
| record_format | Article |
| series | Avian Conservation and Ecology |
| spelling | doaj.art-294480e0525a43448256956c81d7ddf02023-01-02T13:34:18ZengResilience AllianceAvian Conservation and Ecology1712-65682007-06-0121210.5751/ACE-00109-020102109Predation in Ground-Nesting Birds: an Experimental Study Using Natural Egg-Color VariationAurora M. Castilla0André A. Dhondt1Ramón Díaz-Uriarte2David Westmoreland3Museo Nacional de Ciencias Naturales de MadridLaboratory of Ornithology, Cornell UniversityBioinformatics Unit, Spanish National Cancer CenterU.S. Air Force AcademyWe tested the hypothesis that cryptically colored eggs would suffer less predation than conspicuous eggs in the ground-nesting red-legged partridge, Alectoris rufa. We used A. rufa as a model species because it has a wide range of natural egg colors, the eggs are widely available from breeding farms, and nests are easily mimicked because they are scrapes containing no vegetation. The study was conducted in the spring of 2001 in forest and fallow fields of central Spain in Castilla La Mancha, Ciudad Real. We used 384 clutches of natural eggs that were white, white spotted, brown, or brown spotted. Within clutches, eggs were consistent in color and size; among clutches, color differences were distributed across habitats. Clutches were checked once after 2 wk of exposure. Cryptic coloration had a survival advantage that was dependent on the local suite of predators. Rodent predation was nonselective with respect to clutch color; however, avian predation was significantly higher for conspicuous clutches. In addition, there was an interaction of landscape and egg color for avian predation. In forest landscapes, the clutches with highest survival were brown spotted, whereas in fallow landscapes, brown and brown spotted clutches had higher survival than white and white potted clutches. Thus, both the predator suite and the landscape had significant effects on the value of cryptic egg coloration. Our study is relevant for conservationists and managers in charge of restocking programs in hunting areas. The release of other partridge species or their hybrids could result in hybridization with wild partridges, potentially leading to nonoptimal clutch pigmentation and reduced survival of the native species. We therefore recommend that local authorities, managers, and conservationists be cautious with the use of alien species and hybrids and release only autochthonous species of partridges within their natural ranges.http://www.ace-eco.org/vol2/iss1/art2/egg color variationegg crypsislandscape variationnatural selectionpredation |
| spellingShingle | Aurora M. Castilla André A. Dhondt Ramón Díaz-Uriarte David Westmoreland Predation in Ground-Nesting Birds: an Experimental Study Using Natural Egg-Color Variation Avian Conservation and Ecology egg color variation egg crypsis landscape variation natural selection predation |
| title | Predation in Ground-Nesting Birds: an Experimental Study Using Natural Egg-Color Variation |
| title_full | Predation in Ground-Nesting Birds: an Experimental Study Using Natural Egg-Color Variation |
| title_fullStr | Predation in Ground-Nesting Birds: an Experimental Study Using Natural Egg-Color Variation |
| title_full_unstemmed | Predation in Ground-Nesting Birds: an Experimental Study Using Natural Egg-Color Variation |
| title_short | Predation in Ground-Nesting Birds: an Experimental Study Using Natural Egg-Color Variation |
| title_sort | predation in ground nesting birds an experimental study using natural egg color variation |
| topic | egg color variation egg crypsis landscape variation natural selection predation |
| url | http://www.ace-eco.org/vol2/iss1/art2/ |
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