471 
1921.] Bird-Migration by the Marking Method. 
Historical Survey of Bird-Marking. 
Various kinds of marks have been tried or suggested, such 
as parchment tied under the tail with silk, thin metal discs 
glued to the tail-feathers, and indelible stamps on the tail- 
feathers. But all these, besides being clumsy, have the 
great disadvantage of lasting only until the next moult, and 
for both convenience and permanence marks on the feet are 
obviously the best. In early, isolated attempts at marking, 
such crude means as brass wire or silk thread twisted round 
the bird’s foot were used; but in order to allow of an 
inscription, a broad metal ring is necessary. As combining 
extreme lightness with a moderate degree of durability, 
aluminium is to be preferred, and all the more because it is 
easily worked and stamped. 
Complete rings, such as are used for homing-pigeons, are 
of little use for marking wild birds, as they can only be 
placed on very young birds in any case, and not even then 
in the case of birds with nidifugous young, these having 
well-grown feet by the time they are hatched. Furthermore, 
these rings are expensive, as they are cut from aluminium 
tubing instead of from sheet aluminium, and have to be 
stamped when in circular shape instead of on the flat. 
Hence the superiority in every way of the “ split ring,” 
which is a band stamped from a sheet and then folded into 
a circle. The edges are merely pressed together, and a ring 
of this kind, if of small diameter, will keep its shape without 
difficulty. Rings of larger size must either be of thicker 
metal to do this, or must have a clasp of some kind. A very 
simple pattern is one in which the band is longer, and is not 
all used in forming the circle ; two unequal ends are left to 
project outwards side by side at the meeting place, the longer 
being afterwards folded over the shorter, and so forming a 
clasp which, especially if subjected to pressure with a pair 
of pliers, will effectually prevent the ring from coming off. 
It may be mentioned that for Moorhens, Divers, and some 
other water-birds, the rings require to be bent into oval 
shape to fit the much compressed tarso-metatarsus. 
SER. XI.—VOL. III. 2 1 
