Page 765 - Hand rearing birds second

768 Hand-Rearing Birds

Aviaries
The minimum aviary size recommended for these medium‐sized songbirds is 4 × 8 × 4 ft.
(1.2 × 2.4 × 1.2 m) for four to six birds (Miller 2012), but the authors recommend larger 6 × 10 × 8 ft.
(1.8 × 3 × 2.1 m) for three to four birds or 8 × 16 × 8 ft. (2.4 × 4.8 × 2.4 m) for five to eight pre‐release
birds. Aviaries must be safe and predator‐proof. Basic design includes 2 × 4 in. (5.1 × 10.2 cm) wood
frame construction, with ½ in. (1.25 cm) hardware cloth on the outside, fiberglass screen on the
inside, and solid plywood on the bottom 3 ft. of the walls. The wood frame will create a space
between the exterior aviary wire and the interior fiberglass window screen. This important buffer
prevents sneak attacks and strikes through the wire and screen from predators such as accipiters
and free‐roaming cats.
At least one‐quarter of the structure should be fully enclosed with plywood on the roof, back,
and sides (Figure 49.5). This provides shelter and a safe place to roost and escape from view of
predators. Include a double‐door entry, or interior screen door, to prevent accidental escapes upon
entry into the enclosure.
Enclosure substrates can be gravel, sand, turf, dirt, or a combination. You must have the ability to
clean and disinfect. A layer of hardware cloth (1/4 in./0.6 cm wire mesh) should be submerged under
the dirt and gravel layer to prevent intrusions from rats, raccoons, and other predators. A well‐placed,
well‐built structure provides access to sunlight, natural elements, good air circulation, room for full
flight and normal flight patterns (banking, turning, sallying), and a view of the night sky.

­ Pre-release­Conditioning­and Release­Criteria

As prey species, passerines must have strength, stamina, and agile flight to evade predators and
capture food. Pre‐release conditioning in a secure, large outdoor aviary is the best way to support
the development of these skills for a hand‐raised passerine.

Figure­49.5­ Black-headed Grosbeak in an aviary furnished with ample greenery, mixed solid and wire
mesh walls, with natural foods offered for foraging practice.