THE ESSEX FIELD CLUB. 303
8. Feathers grown in late fall and winter have more
pronounced bars than those grown in spring and summer.
9. The presence of a strongly barred feather in company
with adjacent or corresponding feather having no bars
or but faint bars indicates that the strongly barred feather
has replaced one lost from the normal plumage.
These authors were unaware of Dr. Riddle's work until
the completion of their paper.
Two papers on the subject were published by Dr. O. Riddle
(cf. Biological Bulletin, 1907, xii, pp. 165-74 and 1908, xiv, pp.
328-70). I epitomise Dr. Riddle's conclusions. He recognised
two main types of barring. Fault bars or feather defects,
which result from abnormalities of the structure of the feather.
Fundamental bars, which occupy the spaces between the fault
bars. A single fault bar and a single fundamental bar represent
the total of 24 hours' growth. The fault bars appear in that part
of the feather which is developed during the night, probably
between 1 a.m. and 5 a.m. The cause of the fault bar is attributed
to the lowering of the blood pressure, which occurs during the
above-mentioned hours, and which in turn reduces the nutritive
supply of the feather. The question of the hours during which
the bars on crepuscular and nocturnal birds are formed is one
which presents itself. Dr. Riddle refers to the work of Simpson
and Galbraith, who found that the temperature curve of the
Owl is reversed. Dr. Riddle adds that if this is true the blood-
pressure curve of such birds may also be reversed and the fault
bars would probably be formed in the afternoon.
In a summary of his conclusions, Dr. Riddle writes : "The
fault bars occur, normally, in all bird groups, in all plumages,
in all feather tracts, and in all individual feathers."
THE ESSEX FIELD CLUB—REPORTS OF MEETINGS.
SPRING RAMBLE TO UPSHIRE AND HIGH BEACH (852nd Meeting).
SATURDAY, 5TH MAY, 1945. 
An uncomfortable, raw-cold day. with intermittent drizzle (later increasing to
a steady downpour) was not at all conducive to a large gathering ; the surprise was
that as many as seventeen members and friends attended the ramble, in spite of
the unfavourable weather conditions.
The route, which had to be varied because of the wet undergrowth, was from
the "Wake Arms" through the Forest to Woodridden Farm and by footpath to
Upshire (where a short visit to the little Church of St. Thomas afforded the oppor-
tunity for a rest), by lane to Honey Lane Plain and through the Forest to Pinners
Green Lane to High Beach.