well with larger non-passerines such as raptors and gulls but must not be used for
species that are known to be sensitive at the nest during incubation.
4.3.6Mist-nets
One capture method outstrips all others as the option preferred by researchers
today: the mist-net. However, they are of little or no use for larger species
(e.g. pigeons, wildfowl, gulls, and raptors). A mist-net is a vertically erected fine
(almost invisible) net, typically of terylene (beware nylon, which tends to be too
inelastic for bird safety) supported horizontally as net panels or shelvesbetween
a series of strings (shelf-strings) set about 50 cm apart, which are themselves
attached to vertical poles via string loops. The netting forming the shelf must
have sufficient vertical slack in it to form a pocket between the self-strings. Nets
are available in a variety of lengths (e.g. 6-, 9-, 12-, or 18-m) and mesh-gauges
(e.g.c.32 or 60 mm stretched knot-to-knot– larger meshes allow larger species to
be taken) or can be made up from loose material to almost any specification.
Poles can be in the form of aluminum sections (sectioned tent poles can be ideal)
that slot together, or 4-m lengths of bamboo or similar material. The poles, and
net strung between them, are held under tension by guy cords either tied to
vegetation, or to pegs or poles (on mud-flats) in the ground. Birds are caught
when they fly or walk into the net, becoming entangled, and ending up in a pocket
of netting supported from a shelf-string. On entry to a net, birds can spin into
a pocket and become tangled by wings and feet in addition to their heads passing
through the netting.
The mist-net’s ubiquity reflects its flexibility (it can be used in almost any
terrestrial habitat for a wide range of species) and its portability (an 18-m long
net setting 2.5-m top to bottom, folds into a bag weighing less than 0.5 kg), but
not its ease of use because more than any other trapping method (apart from
cannon-netting), mist-netting requires patience, dexterity, and experience if
birds are to be extracted unharmed. However, the ubiquity of the mist-net is also
testimony to the fact that most people can acquire these skills rapidly, and world-
wide many millions of birds have been trapped safely by mist-net for ringing and
release.
To extract a bird from a mist-net, identify the side on which the bird entered, and
then put your hands in the pocket to untangle it until it can be taken by the base of
the legs and carefully drawn away from the net, clearing feet, wings, and head in
sequence. Care must always be taken not to damage flight or tail feathers on extrac-
tion. A very handy tool for the netter, supplied by the BTO, is the Quickunpick,
which is actually a stitch cutter supplied with sewing machines, and which can be
used as a probe to loosen tight netting, or if needs be, to cut a mesh of the net.
92 |Birds in the hand