Page 273 - Hand rearing birds second

Cormorants 261

Figure 15.7 Play-pen-style fenced off area in a larger aviary that allows chicks to have exposure to other
aviary residents and the outside world during the day. Source: photo courtesy of International Bird Rescue.

careful attention should be paid to pool water quality and its effects on plumage waterproofing,
particularly if the birds are eating an oily species of fish.
Use caution when introducing young birds to potential foster parents or other adult birds. Adults
may not accept begging behavior from chicks that are not their own, so it is important to monitor
the situation to ensure the chicks continue to thrive.

­ Preparation­for Wild­Release

Pre‐release housing should be a large aviary with access to water for swimming and diving
(Figure 15.8); this is where birds are weaned and learn to dive, swim, and fly. In the U.S., caging
must conform to USFWS standards found in Minimum Standards for Wildlife Rehabilitation
(Miller 2012); however, it is highly recommended that these standards be exceeded to allow plenty
of room for birds to practice life skills. For cormorants, the minimum recommended housing for
unlimited activity is an 8 ft. (2.4 m) diameter × 2 ft. (0.6 m) deep pool in an 8 × 20 × 10 ft. (2.4 × 6 × 3 m)
aviary. Pools must have an overflow system to allow surface contaminants to run off so that the
birds’ waterproofing will not become compromised.
Cormorant chicks should be thoroughly evaluated for signs of habituation or imprinting at all
stages of rearing, especially when considering release. Since cormorants’ ranges include many
populated areas, birds that are habituated or imprinted carry a significant risk to humans and vice
versa if they show no fear of humans upon release.
When juvenile cormorants are living in an aviary, unobtrusive monitoring should occur to deter-
mine whether the birds are interacting normally with cohorts and are able to navigate their envi-
ronment (i.e. enter and leave pool areas) with ease. Live or dead fish may be tossed into pools in
pre‐release enclosures to encourage natural hunting behavior.
Juvenile cormorants may take short flights in a large aviary, but they need not perform adroit
maneuvers in a captive setting to be released. Release criteria include no physical or mental abnor-
malities, any previous injuries resolved, flight feathers completely emerged, plumage perfectly
waterproof, well‐fleshed body condition, and packed cell volume >40% and total solids >4.0 g/dl.