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Grackles, Blackbirds, and Other Icterids 739

tip and can allow birds to bathe. Adding a few rocks in the middle can be helpful. Disinfect between
groups of birds.
Pre‐release flight caging should be at least 4 × 8 × 8 ft. (1.2 × 2.4 × 2.4 m) for smaller icterids and
8 × 16 × 8 ft. (2.4 × 4.9 × 2.4 m) for larger species such as grackles (Miller 2012). Birds should be in
these aviaries for 7–14 days before release. Do not keep smaller icterids longer than this without
specific reasons (e.g. keeping for molt, recovery from injury). The longer birds are kept in care,
especially when healthy and wild enough for release, the more likely they are to develop stress and
captivity‐related problems (e.g. injury in aviary, infectious disease).
Grackles are fed by their parents for several weeks after they fledge. Wait until almost all the
feathers are in on the face and the bird becomes noticeably restless in the aviary before considering
releasing (Figure 47.4). Usually at this point the eyes are starting to change color and are not as
dark. They are short migrants in the wild, so flight and endurance must be strong.

Release Criteria and Location

For all icterids, make sure the bird can forage and is eating a variety of natural foods on its own.
Observe it surreptitiously in the aviary: can the bird perch, walk, and fly like a healthy wild bird?
Are all birds normally averse to human presence? Condition of flight and contour feathers should
be excellent. Do a physical exam on each bird before release: body weight must be good, mentation
normal, with no signs of disease or injuries. If an individual has any abnormalities, consider hold-
ing it back until the next group is ready for release.
Icterids are diurnal birds and most are highly social. Choose a place for the release where con-
specifics are commonly found. For example: look for flocks of Common Grackles feeding in back-
yards, open fields, or wetlands in the summer and fall. Release birds into a flock of the same
species early in the day, which will allow them to begin the process of establishing themselves in
the social structure, finding food and water, and learning where to roost for the night. Additional
insight on potential release sites can be found by contacting local bird clubs or checking with eBird
online (https://ebird.org). Time releases to coincide with 3 days of expected good weather and mild
temperatures.

Figure 47.4 Common Grackle fledgling nearing release age.