12 Mr. Blackwall’s Extracis from his Zoological Journal. 
manner, retain possession of them; but perhaps it is not so generally 
known, that they sometimes expel the Sand Martins from their subterra- 
neous retreats, at the farther extremities of which they construct nests, 
meagre in dimensions, and scanty in materials, when compared with the 
bulky fabrics which they build in trees, and under the eaves of houses, 
where they are less restricted in room. 
House Martins, before they retire in autumn, are sometimes observed 
to repair their nests ; and I have ascertained, by marking birds of this 
species, that they regularly return to their accustomed breeding haunts. 
It may be remarked also, that they occasionally assist each other in con- 
structing their nests, as I have had several opportunities of witnessing. 
The intelligence manifested by this species will amply repay the observer 
for the attention he may bestow upon its manners and economy. 
It is well known that the Yellow Bunting generally makes a very sub- 
stantial nest, yet, from some internal defect, (for there did not appear to 
be any in its external configuration,) a female of this species, in June 
last, deposited its eggs on the bare ground ; in which situation it sat upon 
them till they were hatched. It is evident that birds of the same species 
possess the constructive powers in very different degrees of perfection ; 
for, though the same style of architecture is usually adhered to, the nests 
of some individuals are finished in a manner greatly superior to those of 
others. In the instance before us, the requisite instinctive capacity ap- 
pears to have been wanting altogether, as it is known to be in the Goat- 
sucker, Cuckoo, Cow-pen bird, and some species of water-fowl. 
THE ROOSTING OF FIELDFARES. 
In the spring of the year 1812, which was cold and wet, being on a 
visit at a friend’s house, near Tamworth, in Staffordshire, I remarked 
that great numbers of Fieldfares prolonged their stay in that part of the 
country till the second week in May, which is considerably beyond their 
usual time of departure. At the close of day, they regularly assembled 
in an extensive wood in the neighbourhood, and roosted on the ground, 
among the withered grass and fern, under the trees and bushes. This 
fact tends to confirm the observation made by Mr. White, (Nat. Hist. of 
Selborne, Letter XX VII, addressed to T. Pennant, Esq.,) that Fieldfares, 
though they frequently perch during the day, always appear to roost on 
