Page 290 - Hand rearing birds second

Herons, Egrets, and Bitterns 279

weeks or become an inspissated mass of dead tissue that may need debridement. However, if the
worm mass begins to look more swollen and yellowish, it has become infected and a course of
antibiotics such as amoxicillin with clavulanic acid (125 mg/kg q12 h) may be needed.
Verminous coelomitis resulting from infestations with Eustrongylides ignotus can often be identi-
fied by wormy ridges crisscrossing a firm, lumpy abdomen (Figure 17.3). This bean sprout‐sized
worm pokes holes in the bird’s stomach and causes abdominal abscesses and adhesions that can
affect peristalsis and organ function and causes significant mortality in young wading birds
(Spalding and Forrester 2008). This can be differentiated from fish in the stomach by palpating the
bird’s abdomen when both empty and with a full meal on board. Monitor the shape and size of the
mass, and how the chick is doing. At International Bird Rescue, it has been noted that birds with
these masses affecting more than half of their abdominal volume, or those where the worm mass
feels like it is penetrating the body wall, tend to do very poorly. In California, this problem is seen
commonly in Green Heron (Butorides virescens) and Great Egret (Ardea alba) chicks, and less
commonly in Black‐crowned Night‐Heron (Nycticorax nycticorax) chicks.

­ Diets

Young herons and egrets in the wild eat a diverse diet that is based on fish but also includes small
rodents, crustaceans, and large insects. Great Blue Herons eat more small mammals than do
smaller herons and egrets. Cattle Egrets are less oriented toward water than other egrets. Black‐
crowned Night‐Herons rely more exclusively on fish than other species. Within and across these

Figure­17.3­ Abdominal mass due to
infestation with Eustrongylides ignotus,
coelomic worms, in a Snowy Egret chick.
Chicks with this problem often have a
palpable firm lumpy mass occupying space
in the abdomen, but the mass does not
always visibly affect the external contour of
the body like in this bird. Source: photo
courtesy of International Bird Rescue.