Page 439 - Hand rearing birds second

432 Hand-Rearing Birds

Figure­26.7­ Least Tern chick in well-heated brooder with a clean feather duster and mirror to provide
company. Source: photo courtesy of International Bird Rescue.

After the chicks are able to thermoregulate – at about 1 week of age for gulls, or 2 weeks for
smaller tern species – the overhead tungsten light can be replaced with a full-spectrum light. In
tern and gull species, metabolic bone disease is rare, but since the birds are reared indoors, full-
spectrum lights over the incubator (or through the door of the kennels) are prudent to provide
chicks with adequate vitamin D production.
Once chicks are able to thermoregulate, the ambient temperature in their enclosure can be
decreased gradually, and they can be moved to a larger enclosure. At about 3 weeks of age for terns,
or 4 weeks for gulls, the chicks should be near 80% of normal adult weight and have primary feath-
ers at least half grown. Small terns will have lost most or all of the downy tufts on the head and
back, larger gull species may still have some down. Gulls and terns at this stage of development are
completely self-feeding, and can be transferred either to a small 6 × 8 ft. (1.8 × 2.4 m) enclosure with
a sand floor and small pool or directly into the final flight aviary.
When first placed outdoors, birds should be monitored to check that they do not get wet or
become hypothermic. Monitoring is especially important if the weather is cool or if any birds are
not completely waterproof. Heat should be provided in a protected corner of the aviary until it’s
certain that all birds are doing well at ambient outdoor temperatures.
Flight cages should have sand floors that are swept of surface debris several times a week. Fresh
sand should be added when necessary. Pools (either concrete or with PVC liners) within the aviary
should have a gradual slope, and they should be drained daily and filled with fresh water or allowed
to overflow to constantly remove any floating potential plumage contaminants. Pools should be of
a size and slope that allows birds to walk in and out to bathe. The minimum access to water recom-
mended for these species is one 45 in. diameter, 10–12 in. deep pool for every four to six birds
(Miller 2012).

­ Weaning

Most terns will start picking up food within 2 weeks of hatch. Some species (Western Gulls) will
pick up dropped food at 3 days of age; some may take a little longer. Individuals may be slower to
self-feed; several chicks grouped together will self-feed more rapidly and are less likely to become