OBSERVED IN' HERTFORDSHIRE ENT 1884 . 
217 
and wherefore ” of the phenomena of migration. During the last 
five years extremely little difference has occurred in the arrival of 
summer migrants. Taking the nightingale as a type of the rest, I 
find that the time of its arrival has varied only from the 9th to the 
14th of April. The swallow has not been quite so regular in its 
appearance, it has varied from the 1st to the 9th of April. 
The very considerable increase and decrease in the nnmher of 
some among our resident species, during certain periods of the year, 
might well claim our attention ; but the subject is fraught with 
difficulty, because it is absolutely impossible to distinguish between 
residents and migrants in a mixed flight of the same species. 
These remarks apply especially to larks, chaffinches, thrushes, 
starlings, and rooks; and their periodical arrival in this country, 
although attributable to a large extent to ever-changing atmospheric 
influences, can be predicated with some degree of certainty. There 
are other species about which no such certainty exists. In my 
report for the year 1882 I alluded to the marvellous influx of jays. 
Prior to that year jays had become comparatively scarce, and some 
difficulty was experienced in obtaining a sufficient supply of their 
gorgeous plumage for the purposes of fly-fishing. During the 
autumn of 1882 the eastern and southern districts of England were 
almost deluged with them. “ I think, Sir, it must have rained 
jays,’’ said a gamekeeper to me, as he pointed out the scores and 
scores that he had killed. Large numbers of these birds have 
doubtless remained with us, and at the present moment jays are far 
more plentiful in our county than was the case five years ago. 
The same remarks apply with almost equal force to our little 
favourites, the gold-crests. In the months of August, September, 
and October, 1882, an immense immigration of these tiny birds 
took place over the eastern districts of England, and gold-crests 
have certainly been more plentiful in Hertfordshire during the past 
few years than they were previously. The subject is a very inter¬ 
esting one, but at present I must not pursue it further. I remark, 
in conclusion, that the term “ Resident,” although strictly applic¬ 
able to any species always to be found within the compass of the 
British Isles, does not imply that the same birds are not migratory 
elsewhere, or that large numbers of them do not come to us from 
abroad and again leave us very constantly. 
It will have been noticed that eight out of the twelve species now 
first recorded in my present paper are water-fowl, and that half of 
these have been taken on the Elstree Reservoir. I am much 
indebted to Mr. E. P. Thompson, of Elstree, for the persevering 
manner in which he has hunted np for me particulars respecting 
the capture of three of them; I am under equal obligation to Mr. 
Henry Lewis for assistance of a similar kind in the neighbourhood 
of St. Albans. Since the death of the Rev. J. Harpur Crewe, 
of Drayton Beauchamp, who kindly supplied me with valuable 
information on several occasions, I have not succeeded in obtaining 
a single ornithological correspondent throughout the Tring and 
Berkhamsted districts. This is much to be regretted; the Tring 
