IOWA ACADEMY OF SCIENCE 
193 
NOTES OP THE FOOD OF THE BLACK CROWNED NIGHT HERON IN 
CAPTIVITY. 
BY B. H. BAILEY. 
While studying the bird life of Eagle Lake in Hancock county, Iowa, we cap- 
tured and brought alive to Cedar Rapids an adult Black Crowned Night Heron 
(Nycticorax Nycticorax Naevius.) It was kept at Bever Park for observation, 
and on account of the scarcity of frogs and fish, various kinds of food were 
presented to it, among which were some white rats that, being prolific, were used 
by the keeper as food for the caged hawks and owls. The Heron seemed to 
take unhesitatingly to these, and would kill and eat a rat with apparent relish. 
When a two-thirds grown white rat was placed in the cage the bird would seize 
it immediately by the back of the neck. By beating and biting, the head, and 
probably the ribs also, were crushed. It was then carried in the Heron’s bill to 
the water pan, where the rat. was immersed several times and then swallowed, 
head first, and entire. Not less than three hours after this performance a sym- 
metrical ball of fur, so compactly felted together that it was with difficulty 
pulled apart, would be regurgitated. Unlike “owl pellets” in only one instance 
did I find any bones or even teeth in this hair ball. On this occasion half of 
the lower jaw with a lower incisor, was found firmly imbedded in the mass. 
The excrement, as is common in this order of birds, was very limy, resembling 
whitewash. The character of the excrement is easily explained by the amount 
of bone these birds ingest, and it is remarkable that teeth are likewise disin- 
tegrated. No hard bodies, such as bone, could be found in the cage, either in 
the excrement, or in the regurgitated mass, with this single exception, which 
was due, no doubt, to the matting of the hair about this bone and tooth before 
the digestive juices could act upon it. 
The readiness with which these mammals were eaten suggests that the Black 
Crowned Night Heron may be a factor of some moment in destroying noxious 
rodents, especially at night, which is their usual feeding time. 
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