INTEODUCTION TO NATUEALIST'S CALENDAR 
"William Markwick, wlio afterwards took the name of Eversfield, 
was an observant Naturalist, and communicated several papers relating 
to British zoology to the Linnaean Society, several of which appeared 
in its transactions. He died in 1813. 
In preparing an ornithological calendar in 1849, we prefaced it with 
the following remarks, which may, with propriety, be reprinted here, as 
although written for ornithology they will generally apply to any 
department of zoology ; they also allude to the author's favorite subject, 
migration. 
The importance of the registration of 'Aperiodic pJicenomena,'^ 
appertaining to animals and plants, has been long acknowledged and 
advocated in different periodicals and works, writing of and devoted to 
natural history ; and sundry calendars have been published, which 
although they contain many points worthy of observation, and were 
sometimes very amply made out, were not within the reach of all 
observers, and did not serve as a guide for the uniform registration of 
the phsenomena. In our numerous works relating to the Ornithology 
of the British Islands, we have many observations and partial lists of 
the appearance and disappearance of our winter, summer, and occasional 
visitants. The migrations ; flocking and congregating of species after 
incubation ; disappearance of certain species, and their occurrence again 
after a period of years have been all noted down. Many of our friends 
have kept private notes of these occurrences, and we have ourselves made 
observations over a period of nearly thirty years ; but all these are neither 
kept to any plan, nor accompanied with notes of the temperature, 
weather, and other circumstances which would have added greatly to 
their value. They are made in various localities, and in various j^ears 
and circumstances ; and however interesting the task, it would entail 
much time and labour to reduce them to any available order. If, then, 
the more important points in the economy of our native species could 
be registered on some simultaneous and regular plan, interesting 
information and details might be elicited, and an insight into the 
laws which regulate their motions and changes, be in a short time 
obtained. 
For the above purpose, a set of Tables have been prepared for the 
present, the concluding number of the " Contributions for 1848," in 
fiuch time as will enable the month of January, with the whole year. 
