Birds. 1389 



or superabundance of food, although it is probable that by such cau- 

 ses their movements are influenced. 



Not the least curious point in the migrations, both of these and the 

 other species of the falcon tribe, is the fact, that birds, at other seasons 

 so much the reverse of gregarious, should to a certain extent migrate 

 in company. That they actually do so, we have indeed no certain 

 evidence, but their simultaneous appearance along a line of coast 

 would seem to indicate it, and the rough-legged buzzard has certainly 

 been observed in pairs in the autumn. Some of these visiters indeed, 

 are birds of the previous breeding season which have never been fixed 

 in any particular locality, but very many, though they have not en- 

 tirely assumed the adult plumage, are birds of the second or third year, 

 whose gregarious nature at this season may be considered as at vari- 

 ance with the usual habits of the genus. 



There are several other species of this class which are observed to 

 congregate either previous to, or at the time of their flight. We have 

 repeatedly noticed this habit in the hooded crows, which just before 

 their departure in spring may be seen gathered in small parties under 

 the sandhills on the coast. These assemblages gradually become 

 larger, until the birds of which they are composed suddenly disappear, 

 and it may be conjectured that they collect in this manner for the pur- 

 pose of settling the period and direction of their flight. 



"Where the Rhine loses his majestic force 

 In Belgian plains, won from the raging deep, 



* * * # 



* *■ * % 

 The stork assembly meets ; for many a day, 

 Consulting deep, and various, ere they take 

 Their arduous voyage through the liquid sky." 



Thomson. 



Yet the hooded crow is, we think, not gregarious in its autumnal mi- 

 gration to our coast, as we have seen solitary specimens before the ar- 

 rival of the main body, and have also seen it arrive singly. 



A large proportion of the wading and swimming birds which 

 are found in this district will be seen by the analysis to be included in 

 the two classes of migrants under consideration. It is highly probable 

 that many of these formerly came under the denomination of summer 

 visitants, and bred regularly in the county, and more than one instance 

 is mentioned in the Catalogue, in which, even at the present day, 

 birds of these divisions have been killed under circumstances which 



