REED WARBLER 



spring are almost invariably males. I have met with one 

 instance only in this district of a female arriving before a 

 male. In reference to this, Gatke writes in his " Birds of 

 Heligoland " as follows : " In the spring in the case of all 

 species the most handsome old birds are invariably the first 

 to hasten back to the old homes as the heralds of reawakening 

 life; these are soon followed by the old females, whose 

 numbers increase, while those of the males decline, and the 

 migration is brought to a close by the younger birds." It 

 must not be understood from this that the migration of the 

 males is completed before that of the female commences, but 

 that the migration of the sexes overlaps, males continuing to 

 arrive with females. It is important that this should be clear, 

 because there seems to be an impression that the times of 

 migration of the sexes are distinct, that the males arrive, and 

 that after a pause the females follow. For instance, the late 

 Professor Newton, referring to this peculiarity, says : " It has 

 been ascertained by repeated observation that in the spring 

 movement of most species of the Northern Hemisphere the 

 cock birds are always in the van of the advancing army, and 

 that they appear some days, or perhaps weeks, before the 

 hens." And he then proceeds to give this explanation : " It 

 is not difficult to imagine that, in the course of a journey 

 prolonged through some 50° or 60° of latitude the stronger 

 individuals should outstrip the weaker by a very perceptible 

 distance, and it can hardly be doubted that in most species 

 the males are stouter, as they are bigger, than the females." 

 Had he known that the migration of the sexes overlaps, that 

 a few males arrive, forerunners of the advancing army, but 

 that afterwards males and females arrive intermingled, it is 

 probable that his interpretation would have been modified. 

 And even if it be granted that the males are the stronger, this 

 cannot account for their outstripping the females by a week, 

 ten days, or still less by a fortnight in a journey of perhaps 

 1,500 miles. To expect them to accomplish such a distance 

 in from four to five days is surely not estimating their 



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