Page 293 - Hand rearing birds second

282 Hand-Rearing Birds

Figure­17.4­ Solitary Black-crowned
Night-Heron chick in an animal intensive
care unit, furnished with a clean feather
duster and mirror for company, sticks for
toes to grab, and diagonally sliced fish.
Source: photo courtesy of International Bird
Rescue.

­ Expected­Weight­Gain

Birds should be weighed daily and weights recorded in each bird’s record until eating reliably in
each stage of housing. New additions to a group of chicks should be monitored closely to ensure
they are finding the food and getting enough. Weight gains and losses within 10% of a bird’s weight
are normal on a daily basis, but any series of weight measures that shows a failure to increase as
expected, or a trend toward decrease over two to three days, should be addressed directly. Hydration
also needs to be monitored and addressed, especially in birds that require nutritional support.
Weights should be measured first thing in the morning to reduce variation due to ingested food,
because young herons and egrets may eat as much as 20% of their body weight in a single meal.
Additionally, individuals at the same development stage, as measured by feather growth, may vary
considerably in size. Males tend to be larger and heavier than females in many species.

­ Expected­Thermoregulation­Progress

The development of thermoregulatory ability is the central benchmark in the hand‐rearing of
orphaned herons and egrets. They are extremely vulnerable to hypothermia throughout their first
8–12 days of life. Their normal body temperature is 103–106 °F (39.5–41.1 °C). It is not unusual for
newly arrived hatchlings and fledglings to register significantly lower body temperatures prior to
stabilization. For this reason, pre‐warmed stabilization environments should be kept standing
ready throughout the season.