XII. 
A NATURALIST’S CALENDAR FOR THE SOUTH-WEST OF 
HERTFORDSHIRE. 
By John Hopkinson, F.L.S., F.G.S., etc. 
Mead at Watford , 22 nd March , 1889. 
The meeting of our Society Reid in May, 1875, was devoted to 
the consideration of periodical natural phenomena, four papers upon 
this subject being read. The first of these was an introductory 
paper, in which I gave a list of the species and a calendar of the 
phenomena recommended for observation by the Meteorological 
Society, the dates in the calendar being compiled from the Eev. T. 
A. Preston’s record at Marlborough, and that of the Bev. L. Jenyns 
(now Bloomfield) at S waff ham Bulbeck, near Cambridge. The 
Cambridge records were from observations extending over the 12 
years 1820-31, and the Marlborough over the 10 years 1865-74. 
The three papers which followed, by other members of the Society, 
were on the plants, the insects, and the birds to be observed. 
The object of these communications was to induce members of 
our Society to observe and record such phenomena, to which the 
name of phenological has been given, and for the following year 
I was able to compile the first of a series of annual reports, con¬ 
tinued to the present time. 
My own record at Watford extends over the 12 years 1875-86, 
but for the first year very few observations were made. For these 
years I now give a naturalist’s calendar for the south-west of 
Hertfordshire, somewhat similar to the calendar for the northern 
border of the county for the 10 years 1877-86 communicated to 
the Society by Mr. Fordham two years ago. The calendar gives 
the earliest, latest, and mean dates of flowering of sixty species of 
plants observed within a radius of about three miles from the town 
of Watford, nearly all the observations, however, having been made 
in the northern half of the area comprised within this radius, and 
therefore on plants growing on a dry subsoil, gravel on chalk. For 
the four species of insects and the eight species of birds in the 
calendar I have not relied entirely on my own observations. As 
they have not been sufficiently numerous, I have included a few by 
other members of the Society made in the district which includes 
Watford, St. Albans, and King’s Langley, extending, therefore, 
about seven miles to the north of Watford. 
In the first column in the calendar are the phenomena observed, 
the rotation numbers in the Boyal Meteorological Society’s list 
being inserted in parentheses. The second column gives the number 
of years of observation. Then the earliest, latest, and mean dates 
are given, the day of the year following in each case the day of 
the month. For comparison I have added the mean dates of the 
longest series of observations of which we have any published 
account,—that of the Bev. T. A. Preston and his coadjutors at 
Marlborough, extending over the 20 jmrs 1865-84. 
VOL. Y.—PART V, 
9 
