316 INTRODUCTION TO NATURALISTS CALENDAR. 



to be observed and registered ; and accompanying the number, there is 

 a duplicate copy, printed on thin paper and with printed address, 

 which it is requested may be filled up and posted in the first week 

 of January, 1850, when, if health and circumstances permit, a summary 

 of the registers and observations returned will be drawn up and printed 

 with an early succeeding number. 



For the better filling up of these tables, the following observations 

 may not be inappropriate : 



The tables and lists of species have been drawn up, as far as possible, 

 to suit any locality ; at the same time, many omissions may have been 

 made, which experience in a future year may remedy, and there may 

 be many things inserted which are not applicable, and may appear 

 useless in certain districts. Thus, the return filled up in Orkney, will 

 produce a very different appearance from one made in the middle or 

 southern districts of England. 



In these returns, it will be very desirable to know the elevation above 

 the sea as nearly as possible ; to have a general register of the tempera- 

 ture and weather, with a short description of the character of the 

 country and its vegetation around the localities where the observations 

 are made. In the curious and interesting subject of migration, particular 

 attention is desired. The average temperature at the times of appear- 

 ance and departure ; the direction of the wind ; the general character 

 of the weather ; the condition and progress of vegetation, should all 

 be observed. It might be supposed, that the arrival of the migratory 

 species in other countries would be influenced more by the climate of 

 that from which they departed than of that to which they came ; that 

 an earlier frost, or mild weather, would have the effect of driving them 

 away or inducing them to prolong their departure ; in this country, how- 

 ever, though a cold autumn has an evident effect on the time of the depar- 

 ture of the swallows, and many of our summer birds, a mild spring does not 

 always hasten the departure of the winter visitants. The arrival of some 

 summer birds, as the wheatear, does not seem at all influenced by the 

 mildness or continued severity of the spring here ; but we have observed, 

 that mildness and advance of vegetation in this country does make a differ- 

 ence in the time of appearance of several species, particularly the Sylviadce ; 

 and it may be asked, whether the progression of these and others from 

 Southern Europe and Africa is gradual, advancing with the seasons ] 

 The laws which regulate the migratory zone of some species are not, 

 probably, applicable to such as appear to start at once and fly to their 

 destination. The great mass of swallows depart from this country at 

 once, but the appearance of their numbers is somewhat more gradual. 

 The Sylviadce, appear gradually. The migral/ory thrushes, again, come 

 and depart at once. So also do the snipes, woodcocks, and others of 

 the Scolopacidce. If resident on or near the sea-coast, attention should 

 be paid to the ornithology after remarkable storms, particularly during 

 March and April, October and November, and both on the coast and 

 inland, during these months, when migration takes place, and the young 

 are leaving their breeding places and congregating, many rare species 

 have been met with, driven out of their ordinary tract ; and vast flocks- 

 of species generally few in number, sometimes in the same way appear, 



