THE BIRDS OF THE GREEN LANES. 113 



shows us that during the Glacial period the Sahara 

 was a sea, so that there has been a good geo- 

 graphical reason, both before and since that era, for 

 our migratory birds reaching their southern limit 

 in that particular latitude. 



In our walk along the river side, it may be that 

 we disturbed a stately -looking Heron (Ardea cinerea\ 

 who had previously been steadily looking at the 

 water as if he contemplated suicide. This bird was 

 once very commonly distributed, and still is in 

 certain localities. It is a pity it should have been 

 so hunted down, for it forms a conspicuous object in 

 river scenery. In Norfolk it is still common in 

 many parts, and pairs may not unfrequently be seen 

 flying over the city of Norwich in the daytime. But 

 perhaps the place where it is unusually abundant is 

 on the banks of the Orwell, from Ipswich to Harwich. 

 Here, at low water, you may see scores of these birds 

 fishing. It is quite as abundant in the river Deben, 

 which runs up to Woodbridge ; and also in the 

 Stour, which joins the Orwell near Harwich. The 

 extensive mudbanks of these estuarine rivers would 

 look quite solitary were it not for the numerous 

 herons and gulls. It is an unsocial bird, and prefers 

 solitude to company. Still, you may generally 

 expect to see a second heron not far off, if you see 

 one. These birds generally roost in trees, and a 

 collection of their nests forms a "heronry." The 

 fact of a wading bird nesting in a tree is very 

 unusual. Elm trees appear to be the favourites, 



I 



