Birds. 2189 



another part of the wood, I followed him, and on the 8th of May, 1848, had the 

 pleasure of finding the nest near the top of a tall spruce fir : its size was nearly the 

 same as that of the redpole, and the materials are also similar : it contained four eggs, 

 of about the same size as those of the goldfinch. — /. Dale, in a letter to W. Proctor, 

 of the Durham University Museum. 



Rooks Building. — The rooks are certainly a punctual people in their building, and, 

 no doubt, in their other operations. But I was not aware, till I read Mr. Lawson's 

 note (Zool. 2145), that they were ever supposed to be exact to a day. The following 

 dates, accurately noted down by myself, record the day of the month on which the 

 rooks were observed to begin carrying sticks for building for several years past. These 

 dates, I should observe, relate solely to the rooks on the premises here ; and I mention 

 this, because I have reason to think that in some other places in this neighbourhood 

 they commence building rather earlier. 



1831. Rooks began to build March 9. 



1832. Do. 



„ 8. 



1833. Do. 



„ 9. 



1834. Do. 



„ 10. 



1835. Do. 



„ 10. 



1836. Not recorded. 





1837. Rooks began 



to build March 9. 



1838. Do. 



„ 11. 



1839. Do. 



„ 3 ; but made little progress till about 13th 



1840. Do. 



„ 11. 



1841. Do. 



„ 7. 



1842. Do. 



„ 11. 



1843. Not recorded. 



1844. Rooks began to build March 10. 



1845. Do. „ 12 ; severe frost 



1846. Do. „ 5 ; very busy. 



1847. Do. „ 12. 



1848. Do. „ 6. 



It would appear from the above dates that the more general period at which rooks 

 begin to build is from the 9th to the 12th of March. 



I may perhaps raise a smile by saying that I have more than a strong suspicion 

 that rooks have some instinctive knowledge when a tree has become unsound, and 

 consequently unsafe, or in danger of being blown down, and that they carefully avoid 

 occupying such trees for the purpose of nidification. The largest elm tree on the pre- 

 mises here — a very large and fine one — never had a rook's nest in it, within my recol- 

 lection, since the rookery has been established, except that one year a late pair, that 

 appeared to have been expelled from the rest of the community, built in one of the 

 lower pendant branches of the head of the tree, — a rather unusual position. I am not 

 sure that the same occurrence might not have taken place a second year ; but, with 

 these exceptions, the tree, to my surprise, was invariably unoccupied, though it ap- 

 peared to be extremely well suited for the purpose, and other elms hard by were clus- 

 tered with nests. I had myself long been aware that this large elm, though it was 

 not going to die of old age, was yet, from some unknown cause or other, getting into 

 a bad state of health ; evidently its constitution was impaired ; it produced but a thin 

 spare crop of leaves, and these diminished in size, and they turned colour prematurely 

 VI 2 H 



