CHAP, XVII.] SMALLER SPRINU BIRDS. 14i 
their long absence and weary flight, and either repairing their 
old residence or building a new one. 
Great numbers of sand-martins build in the banks of the 
river, returning to the same places every year, and after clearing 
out their holes, they carry in a great quantity of feathers and 
dried grass, which they lay loosely at the end of their subterra 
nean habitation. 
The swifts appear always to take up their abode about the 
highest buildings in the towns and villages, flying and screaming 
like restless spirits round and round the church steeple for hours 
together, sometimes dashing in at a small hole under the eaves 
of the roof, or clinging with their hard and powerful claws to 
the perpendicular walls; at other times they seem to be occn- 
pied the whole day in darting like arrows along the cours: of 
the burn in pursuit of the small gnats, of which they catch great 
numbers in their rapid flight. I have found in the throat of 
both swift and martin a number of small flies, sticking together 
in a lump as large as a marble, and though quite alive, unable 
to escape. It is probably with these that they feed their young, 
for the food of all swallows consisting of the smaller gnats and 
flies, they cannot carry them singly to their nests, but must wait 
till they have caught a good quantity. 
We are visited too by that very curious little bird the tree- 
creeper, Certhea familiaris, whose rapid manner of running 
round the trunk of a tree in search of insects is most amusing. 
Though not exactly a bird of passage, as it is seen at all seasons, 
it appears occasionally to vanish from a district for some months, 
and then to return, without reference to the time of year. I 
found one of their nests built within an outbuilding, which the 
bird entered by a small opening at the top of the door. 
