Ward Michael P
Department of Animal Biology, University of Illinois-Urbana-Champaign, 201 Shelford Vivarium, 606 E. Healey Street, Champaign, IL 61820, USA.
Oecologia. 2005 Oct;145(4):650-7. doi: 10.1007/s00442-005-0179-0. Epub 2005 Oct 13.
In migratory birds individuals may prospect for potential breeding sites months before they attempt to breed and should use the cues most predictive of future reproductive success when selecting a breeding site. However, what cues individuals use when prospecting and which cues are used in selecting a breeding site are unknown for most species. I investigated whether yellow-headed blackbirds (Xanthocephalus xanthocephalus) prospect for future breeding sites and whether they select breeding habitats based on food availability, male or female density, or the average number of young produced per female in the previous year. Although it is often assumed that migratory birds prospect for potential breeding sites at the end of the breeding season, I investigated this by recording all visits to sites early and late in the breeding season. I found that males and females who visited sites other than the site at which they bred were more likely to disperse than individuals only observed at the site where they bred, and that males and females were more likely to prospect late in the breeding season. Both food availability and density in year(x) were not predictive of the number of young per female in year(x+1); however, the number of young produced per female at a site in year(x) was predictive of the number of young per female in year(x+1). As expected, dispersers used the most informative cue, the number of young per female and moved to sites with a relatively high number of young per female. This study suggests that individuals prospect for potential breeding sites late in the breeding season when they can use information gathered from the reproductive success of other individuals (i.e., public information) to select a breeding site.
在候鸟中，个体可能会在尝试繁殖前数月寻找潜在的繁殖地，并且在选择繁殖地时应使用最能预测未来繁殖成功率的线索。然而，对于大多数物种来说，个体在寻找繁殖地时使用哪些线索以及在选择繁殖地时使用哪些线索尚不清楚。我研究了黄头黑鹂（Xanthocephalus xanthocephalus）是否会寻找未来的繁殖地，以及它们是否根据食物可获得性、雄性或雌性密度，或上一年每只雌性所产幼鸟的平均数量来选择繁殖栖息地。尽管通常认为候鸟在繁殖季节结束时寻找潜在的繁殖地，但我通过记录繁殖季节早期和晚期对各个地点的所有访问来对此进行了研究。我发现，访问过繁殖地以外其他地点的雄性和雌性比仅在其繁殖地被观察到的个体更有可能扩散，并且雄性和雌性在繁殖季节后期更有可能进行寻找。年份（x）的食物可获得性和密度都不能预测年份（x + 1）中每只雌性的幼鸟数量；然而，年份（x）中一个地点每只雌性所产的幼鸟数量可以预测年份（x + 1）中每只雌性的幼鸟数量。正如预期的那样，扩散者使用了最具信息量的线索，即每只雌性的幼鸟数量，并迁移到每只雌性幼鸟数量相对较多的地点。这项研究表明，个体在繁殖季节后期寻找潜在的繁殖地，此时它们可以利用从其他个体的繁殖成功中收集到的信息（即公共信息）来选择繁殖地。
