82 BIRD-LIFE OF THE BORDERS. 



Pipits are the most numerous ; and besides these, I have 

 noticed in some seasons, very great numbers of Redstarts (all 

 immature), sometimes also the tiny Golden-crested Wrens, 

 right out in the middle of open turnip-fields. The quantities 

 of birds of difierent kinds sometimes congregated in a single 

 field preclude all possibility of their being the ordinary natives 

 or residents of the neighbourhood. Unquestionably they are 

 birds on migration, though many of them belong to species 

 which are not popularly supposed to be migratory. There 

 are, however, very few species which are not migratory to 

 some extent. On examining their seasonal distribution 

 throughout the year (which is the only true test), very few 

 species indeed will be found to remain actually stationary 

 during the twelvemonth ; the number of such might almost 

 be counted on the fingers. 



The subject of migration has already been discussed 

 generally when dealing with the spring season, and 

 it is unnecessary to revert further to its general scope 

 or character. But the phenomenon is a bi-annual one ; 

 there is the vernal movement northwards, and we have now 

 reached, in autumn, its second and converse phase. In 

 September the feathered world is on the move ; throughout 

 Europe, almost every individual unit is a traveller. They 

 move in battalions or in handfuls ; some traverse thousands, 

 others hundreds of miles ; there are long-winged forms that 

 span the world, apparently without rest or eftbrt ; the 

 Curlew -Sandpiper, for example, passes from Arctic to Tropic 

 within a few weeks — perhaps days — and by changing hemi- 

 spheres at each equinox, eliminates the element of winter 

 entirely from its little life. Others travel more slowly, or 

 by stages, or. on the other extreme, like the Brent Geese, 

 cling so tenaciously to hyperborean shores, that at no period 

 of the year are they ever fairly out of sight of ice and snow. 

 Another section is of less extensive mobility, and a few are con- 

 tent with a merely local change of residence. Then, again, ver- 

 tical altitude and longitudinal distance (in a north and south 

 direction) are equivalents ; that is to say the physical 

 conditions of existence on a fell plateau of 3,000 ft. elevation 

 above sea level in our islands, may be exactly analogous with 



