THE SWALLOW 
building or tree. The Swallow becomes increasingly 
interesting in autumn, when its gregarious instincts are 
most developed. Many pass the Metropolis on migra- 
tion. 
The adult Swallow, readily distinguished from the 
Swift and the two species of British Martins by its uniform 
steel-blue upper parts and long, slender outermost tail- 
feathers, has the forehead and throat chestnut, the upper 
parts and a broad pectoral band blue shot with purple ; 
the wings and tail are black shot with green, the latter 
long and acutely forked ; across the tail is a row of circular 
white spots ; the under parts are white slightly suffused 
with buff. Bill black; tarsi and toes black ; irides brown. 
Length 8% inches (of which the long slender outermost 
tail-feathers measure nearly 5 inches). ‘The nestling has 
the chestnut paler, the white spots on the tail pale chest- 
nut, and the outermost feathers are much shorter. 
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