satrow said:
Maybe Goldies win individual battles because of their greater manoueverability (longer tail), or higher speed? Andy.
Hi Andy,
Here's some quotes from that British Birds paper (some snips for brevity)
Michael
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"Golden Eagles are strongly dominant over White-tailed: in Norway, I once observed at first-winter male displace seven White-tailed Eagles in less than ten seconds, and on no occasion was a White-tailed Eagle able successfully to defend a carcase from an attacking Golden Eagle; in those few cases where a White-tailed displaced a Golden Eagle, the latter had invariably been feeding for some time beforehand."
"Golden Eagles are also stronger fliers, and have longer legs and a wider talon span, and they consequently prevail in aerial conflicts."
"The above data may initially suggest that Golden Eagles would competitively exclude White-tailed Eagles in the long term. The evidence from Scotland however indicates that it is White-tailed that ousts Golden from home ranges, despite its being inferior in direct competition. ..... The reason appears to be indirect competition. In western Scotland, White-tailed Eagles enjoy a wider and more varied food base than Golden Eagles; this provides alternative sources when the main sources are limited. In addition, carcases are not permanently defensible resources; dominance may determine which species eats first, but the White-tailed Eagle will eventually get its fill. Competition for carrion is therefore indirect (the removal of a later meal for the Golden Eagle), not direct."
"Raptors adapted more towards a scavenging role and passive sit-and-wait hunting, as is the White-tailed Eagle, typically have a longer, more efficient gut (at the expense of speed and manoeuvrability) than more active hunters such as the Golden Eagle. This results in relatively more efficient nutritional use of shared food resources such as carrion: in other words, White-tailed can survive for longer on less food."
