通常，年轻的蓝莺将会在这些地方筑巢，因为有浓密灌木的首选的筑巢点已经被更年长的、地位更高的蓝莺所占领了。

It is usually the younger warblers that nest in these areas because the preferred spots where there are a lot of shrubs are taken by the older, more dominant birds.

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相比在树上筑巢的同种类雏鸟，在地面筑巢的鸣禽雏鸟会发出频率更高的乞食叫声。

The young of ground-nesting warblers produce begging cheeps of higher frequencies than do their tree-nesting relatives.

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人们发现，录音机在播放树上筑巢的鸣禽的乞食叫声时，比起在播放地面筑巢的鸣禽的乞食叫声时，鸟蛋被攻击的几率明显增大。

The eggs "advertised" by the tree-nesters' begging calls were found bitten significantly more often than the eggs associated with the ground-nesters' calls.

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