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reunification. This should include a thorough physical exam including lung/air sac auscultation,
blood lead level, and an un‐positioned awake radiograph to look for metal opacities. Once the
chick is deemed healthy, the original lake where the chick was found must be scouted. Are both
parents present? Are there any other chicks? What size are the other chicks compared to the cur-
rent chick? How confident are you that this is the correct set of parents? If the answers to all these
questions are known and favorable, reuniting may be possible. However, this does not guarantee
the reunification will be successful. It is recommended to be ready for rescue should the identified
adult loons turn on the chick. If a sibling is present, it may or may not be aggressive toward the
chick or outcompete it for food. Additionally, if the chick was in captivity for an extended period
of time, the parent loons may have already re‐nested.

Fostering

Fostering a chick to a different set of parents often doesn’t work. The pair may already have chick(s)
who will aggressively drive away the stray chick or the parents may recognize the chick as foreign
and drive it away or kill it themselves. Rarely, fostering has appeared to work; however, long term
follow‐up was not possible (Marge Gibson, pers. comm.). Other methods that appear to work
include separating the native chick from the parents, and placing the native chick next to the foster
one, so the parents are confused about who is who and they don’t see you adding another chick
(Kevin Kenow, pers. comm.). Anecdotally, the younger the chick is, the more successful the foster-
ing is likely to be. Adult loons are difficult to maintain in captivity owing to stress and husbandry
standards, and therefore aren’t kept as foster parents or exhibit animals. Captive adult loons under-
going rehabilitation may attack a foreign chick introduced to its enclosure.

­ Captive­Diet

Common Loons primarily eat a variety of fish (cisco, perch, suckers, small white fish, common
and golden shiners, and trout) but are opportunistic when choices are limited. Wild loons have
been known to consume crayfish, aquatic insects, amphibians, and rarely vegetable matter in
addition to fish (Barr 1996). Loon chicks under 5 days old have been observed to eat various lar-
vae and adult insects found on the surface of lakes, such as dragonflies, waterbugs, and whirligig
beetles (Barr 1996). It is likely loons seen pecking at vegetation are eating invertebrates within
the vegetation. However, some rehabilitators have noticed repeatedly that young loons will
eagerly seek out and consume decayed and fresh vegetation as soon as they are placed in a natu-
ral enclosure; additionally, one rehabilitator has noticed a few instances in which a young loon
appeared to have digestive problems that improved after being offered decayed leaves (Diane
Winn, pers. comm.).
In the rehabilitation process, fish have been provided as the primary food source. The maximum
size of fish offered should correspond to the size of the chick’s beak/gastrointestinal tract as loons
swallow their prey whole. Small to medium sized fish (10–70 g) are preferred as larger fish can be
difficult to swallow. Crappie minnows (i.e. from a bait shop) work well for smaller chicks, whereas
fathead minnows and small suckers are excellent for larger juveniles. Other fish species can be
used but may be prohibitively expensive or hard to acquire alive. If possible, a variety of fish is ideal
for nutrition and hunting practice. Different fish species have different evasion tactics, speed, and
nutritional composition.