DARVIC rings must be opened by hand or with strong circlip pliers before being
closed on the leg. Note that some countries will not have as large a range of ring
sizes available as in the United States and the United Kingdom so that either rings
will have to be overlapped (without covering the inscription), cut down in the field
or special arrangements made to permit the use of rings from another country.
Color-rings are often used on their own for behavioral–ecological studies but
have limitations. Not all colors are identified with equal facility under field con-
ditions (at range, on short tarsus etc.), and some colors change (light blue, light
green, yellow, and mauve) over time, especially under tropical conditions. For
small species, bands with combinations of stripes with different widths may be
better than letters or combinations of different-colored rings. Celluloid split
rings are also prone to cracking and falling off, in which case small split DARVIC
rings are better. It is generally wise to glue plastic rings, especially in hot coun-
tries where temperatures may be high enough to open the rings. It should also be
noted that color-rings are thought to cause deformity in some short-legged
species such as Tyrannid flycatchers (especially noted in Mionectes oleagineus).96 |Birds in the hand
Fig. 4.1Standard ringing kit consisting of (left to right) bird bag, metal rings of
various sizes (the plastic “string” labelled 2.3 carries 100 rings of 2.3 mm internal
diameter), field logbook, two sizes of ringing pliers, balances (the bird is placed in a
container, which is then clipped to the balance), and stopped rules for measuring wing
and tarsus lengths. (Photo: Andrew G. Gosler)