Page 530 - Hand rearing birds second

528 Hand-Rearing Birds

Any form of calcium supplementation may be used that can be measured precisely enough to
add the elemental calcium required. Calcium glubionate comes in a convenient pediatric suspen-
sion that provides 23 mg/ml.
Various other diets have been reported as successfully used for raising young hummingbirds. It
is the author’s opinion, however, that successful feather development cannot be achieved unless
the foods contain large amounts of animal protein with the amino acid profile required for a grow-
ing insectivore (MacLeod and Perlman 2001). Indeed, personal communications with numerous
rehabilitators have revealed poor outcomes using commercial diets based on soy protein for both
hummingbirds and passerines (Elliston and Perlman 2002). The author strongly recommends
against using any commercial hummingbird diets that contain significant amounts of soy protein.
These diets have been known to cause gastrointestinal stasis in young hummingbirds and do not
provide adequate types or quantities of protein for growing birds (Elliston and Perlman 2002).
Although these products may be more convenient to make, the younger the bird in question is
started on these inadequate diets the higher the probability that they will grow substandard feath-
ering or suffer greater mortality rates. Nektar‐Plus is meant only for adult birds and is inappropri-
ate for growing chicks without the additional supplemental animal‐based slurries suggested.
Because hummingbirds have evolved eating insects, there is little reason to believe they can utilize
the vegetable protein provided by soybeans.

Fledglings­and Adults

If fledgling and adult food contains 20 mg/ml of protein, eating 5 ml/day will provide the approxi-
mate amount needed to sustain an adult’s protein requirements. It has been observed that the older
the bird is, the more personal the preference may be for sweetness. Adjustments for taste may be
needed with small additions of sugar to coax the bird into readily drinking presently available diets.

Feeding Procedures

The best way to approach meeting the nutritional needs of hummingbird chicks may be to just do
what the mother hummingbird does: stuff the little crops with insects at every opportunity. Begin
each day with fresh diet. Refrigerate all liquid diets between feedings, or keep the day’s food in a
thermos filled with ice. Whey is available in several consistencies, and individual measuring
spoons may vary considerably. It is important to weigh powders until the relationship of volume to
weight has been established for each individual’s equipment.
Some rehabilitators have adopted the technique of putting insects in the fluid to deliver by
syringe (Van Epps 1999). Because some birds may regurgitate when fed insects mixed into their
liquid diet, the author prefers to use catheters that are too small to pass whole insects (except daph-
nia, the water flea) and to feed whole insects with forceps (Figure 34.2). Accurate assessment of a
bird’s tolerance for solids in the crop, and maintenance of hydration, is possible by feeding solids
and fluid separately. However, another option is to create a slurry by grinding insects and adding
an appropriate amount of calcium to balance the phosphorus content of the insects (0.03 ml 23 mg/
ml calcium glubionate per 100 mg insects fed) (Table 34.5). There may be fewer problems if the
slurry and Vivonex Plus mix are fed alternately as the crop empties.
As the caregiver and bird become accustomed to the feeding techniques, feeding becomes easier
to accomplish. Packing the crop first with insect and arthropod slurry until the bird ceases to gape,
and adding vitamin‐enriched liquid elemental protein mix, if the bird will accept it, every