By Donald Bruning, Ph.D.
Zoos and aviculturists have kept and reared insectivorous birds for many years. However, success has been restricted to a relatively few species. Many factors come into play when planning a breeding program.
1st You must provide an adequate diet.
2nd You must have pairs or an appropriate breeding group.
3rd You must have a suitable facility.
4th You must provide suitable nesting areas and materials.
5th You must provide proper environmental conditions -light, humidity, etc.
6th Careful observation and records are extremely important.
Birds must be individually marked or identifiable. The natural habitat and nest structure for each species must be carefully considered. Once the birds produce eggs, the first major hurdle is over and now the real work begins. A number of decisions are now needed.
First, are the eggs to be left with the parents or removed for artificial incubation:
Ideally, the eggs can be left with the adults for incubation and rearing of the chicks. This is certainly the best way, but it also reduces production and may reduce the success ratio of the-nest since chick mortality is generally high. Even so, this is the preferred method.
If the eggs are to be removed, a suitable artificial incubation system must be operating and ready to receive the eggs. Once again, the longer the eggs are left with the parents the better their chances of hatching, but this results in fewer offspring as recycling time is increased. Incubation time, temperature and humidity are critical. We have found 97.5° F with 68% relative humidity are critical. We have found 97.5° F with 68% relative humidity works best for us with passerines. Except under unusual circumstances, the eggs should not be washed or handled any more than absolutely essential. Personnel handling eggs should wash their hands before handling eggs, as oil from fingers can adversely affect hatchability. Most eggs must be turned regularly and benefit from a daily cooling period. The eggs should be regularly candled to determine fertility and follow development.
Eggs should be moved into a separate hatcher once they pip. The humidity in the hatcher should be as high as possible. We regularly spray the inside of the hatcher and the hatching eggs with distilled water from an atomizer spray. Frequently eggs can be removed at this stage from nests where the parents have a record of not caring for their chicks.
A newly-hatched chick should be allowed to dry off in the hatcher. Altricial chicks should then be moved into another hatcher or an infant isolette incubator where temperature and humidity can be carefully maintained. The chicks should be placed in a suitable nest structure which allows them either small twigs or other material for gripping with their feet. Unless a proper substrate is supplied, leg problems are likely to develop. The material used will depend on the species involved. Green wood hoopoes develop severe leg problems if they cannot grip their nest with their tiny feet. A cork bark nest is ideal as they grip it just as they would the inside of a natural tree hollow nest.
Frogmouths have caused problems by swallowing the sticks used in their nests to prevent leg problems. As a result, the sticks must be changed in size every few days so that frogmouths have good footing but cannot swallow the sticks.
Once you have the chick, records become essential. You must maintain records of the chick’s weight along with what and when it is fed. A carefully planned schedule is important at this point. Normally a chick’s weight will drop the first day but should start to increase as soon as the chick starts feeding. The greatest danger at this point is to overfeed the chick because it continually gaps for food. The amount of food should increase gradually. Chicks can be fed very small amounts hourly the first day from 6:00 or 7:00A.M. to 6:00 P.M. Most chicks are far better off if they are not fed overnight. Most chicks are naturally only fed during the daylight hours.
Defecation of the chick becomes a critical factor and should be monitored carefully. Amount, frequency and form of the defecation tell a great deal about the progress of the chick. We have worked out a schedule for Tawny Frogmouths whereby we feed the chick until it reaches 25 grams, and then it is given no more foV until it defecates the first time. Then the chick can be fed until it reaches 35 grams or defecates a second time. Once the chick has defecated twice, it is well on its way and grows rapidly.
The diet of the chick is critically important. Ideally, the diet should be as close to natural as possible. This is usually impossible and an artificial diet must be used. A good basic diet is essential.
First, we try to determine what the parents feed to their chicks and utilize whatever the parents use. However, we realize that we must maintain a good balanced diet so we start with certain basic commercial diets and then modify them as necessary to satisfy specific chicks.
Gaines dog meal and baby mice are the two most commonly used items for our insectivorous birds. Moistened Gaines meal is readily accepted by most chicks. Tiny pieces of baby mice serve as a good substitute for most live insects. Commercial turkey starter and grower form the basis for our diet for adult insectivorous birds.
Feeding a small chick can be quite a challenge. Newly hatched chicks may not be able to hold their heads still while gapping or some chicks are simply too weak to hold up their heads. In these cases, the chick’s head must be held or propped up carefully so the chick can be fed. Pieces of food must be very small. This helps the chick swallow the food and helps prevent overfeeding. Overfeeding is a very serious potential problem during the first few days. It is far better to have an underfed, hungry chick than an overfed chick that is no longer interested in food. Everyone who cares for small chicks finds it very difficult not to give the chick just one more piece of food. Frequently that one extra piece makes the difference between life and death. This is something that we all learn the hard way. Frogmouth chicks are a good example; also Fairy Bluebirds.
The closer we can simulate natural conditions, the greater our chances of success. During the first few hours chicks are fed very small bits of food at intervals of every one or two hours. It is very important that everyone caring for the chick or chicks under- stand what is to be fed and how frequently. We have developed feeding charts to guide any keeper on the specific care of each species.
Most chicks should be fed only during daylight hours. Overfeeding or excessive buildup of waste materials can be serious threats to the welfare of a chick. Early attempts at hand rearing Fairy Bluebirds failed because they were overfed at night and became fouled in their own droppings.
Once the chicks are eating on a regular schedule and have regained their hatching weight, they are ready for a gradual and continual increase in food. Healthy chicks start slowly but grow more and more rapidly with each passing day.
Any change in the growth rate should be a warning flag of potential problems. Long legged birds are particularly susceptible to a sudden spurt of growth, resulting in leg problems. On the other hand, any sudden decrease in the growth rate may signal the onset of infection, disease or parasites. Inadequate or improper diet usually manifests itself within the first forty-eight hours or after five to seven days.
Lack of interest in food, change in body coloration and diarrhea are three additional indicators of serious problems. Time is of the utmost importance. Any delay will generally result in the chick dying. We have found that being prepared with medication can save many chicks. A veterinarian’s advice is needed to determine what medication is needed. However, once a veterinarian recommends a treatment, you should be prepared to start treating a chick immediately when symptoms manifest themselves.
Monitoring the defecation of the chicks is extremely important. Proper fecal sacs or loose droppings are good indicators of the chicks’ health.
The nest structure must be kept clean and supplied with the proper substrate.
Hazards in the nest or in the incubator must be avoided, such as holes, grates, cracks, wires, fans, etc.
As the chicks grow rapidly, they can be fed less frequently and gradually the amount of each feeding can be increased. The progress of the chicks can be monitored by their growth rate, their appetite and the development of their feathers and legs.
The next critical period comes when the chicks are ready to leave the nest. A dramatic weight drop and a decline in acceptance of food are common occurrences at this time. Frequently the droppings of the chick will change from fecal sac to adult soft droppings at or a few days before fledging. Chicks should be gradually converted onto an adult diet before fledging as it is much more difficult to alter diet after fledging. Most chicks will begin to eat on their own shortly after fledging. Hand feeding should continue, however, until chicks are definitely feeding on their own. Hand feeding should stop immediately after self feeding starts. If hand feeding continues too long, chicks are more likely to be imprinted, tame or simply won’t eat on their own.
Chicks removed from their natural nest just before fledging should be treated just like hand reared chicks. Frequently naturally reared chicks will refuse to eat and as a last resource must be force fed. They most rapidly accept food left in pans for them. Getting chicks to eat the adult insectivorous diet can frequently be stimulated by placing mealworms into a shallow pan of the prepared insectivorous diet. The movement of the mealworms attracts their attention, and they soon learn that the other material is food.
Now that the chicks are on their own, they should be cared for like any other birds. However, a great deal of care and observation is required when these birds are moved into any new surroundings. Unless careful observation is maintained when the chicks are introduced to others or into new exhibits, the mortality rate will be high.
Chicks reared in captivity seem to show much greater success in breeding and rearing their own chicks.
These are just a few pointers that we have found to be useful and hope some of these ideas may help you.