Hand Rearing Southern Yellow-billed Hornbills

John Heston

Abstract


On the evening of April 2, 1983, I received an urgent call from work. A couple of large trees had fallen, due to high Santa Ana winds, and another was threatening to crash down on one of the bird facilities. When I arrived and began relocating birds that may have been in danger, I kept noticing that something just wasn't right about the scenery several yards up the hill from me where another complex of cages was located.

When I investigated further, I discovered that the facility was mangled by a giant redwood tree that had uprooted. The damage was so extensive that the floor of one cage was now eye level, and the rest were wrenched beyond repair. It was only because the incident occurred at night-and fortunately a very dark one-that none of the birds escaped.

Of the species of birds that had to be relocated was a pair of actively breeding southern yellow-billed hornbills (Tockus flavirostrus leucomelas). The female, after a period of 58 days, had just broken herself out on March 28 and both parents were feeding four young that remained in the nest box. Ideally, I was hoping that the parents would continue to feed the chicks, despite being relocated; but after 12 hours or so things dido' t look very prom1smg.

After considering some alternatives that we could employ to raise the young ourselves, I decided to let them emerge as naturally as possible instead of, for ex-

 

ample, removing the young immediately and raising them outside the nest box. I moved the nestbox to our main work area; set it up in a convenient location; and I constructed a wire cage around the front to contain the fledglings.

Even though it had been 18 to 20 hours since they had last been fed by the parents, they were at first, still reluctant

 

to accept food from a human hand. From within their capsule, they seem to have sensed that something had gone awry from the way nature had intended. After persistent offerings they soon came around and in a couple of hours were accepting food voraciously, as the following randomly chosen feeding records will attest.

 

At the start of the feed session, the young squeal loudly as they snatch the food from the keeper's hand; but as the session progresses, they will usually settle down and accept the food quietly.

The chicks are tidy little creatures, constantly "cleaning house", i.e., discarding bits of this and that through the small opening in the nestbox. I began placing a cup directly under the slit and was able to collect-what they regard as-trash. Bits of feces, small pieces of detritus, whole or pieces of dead insects, other rejected food, etc., were collected.

Immediately after setting the situation up, it became apparant that one more modification would be necessary. I first realized this through the lens of my camera while attempting to photograph the arrangement. While focusing, a tuft of white feathers-the type that would be found around the vent of a bird-appeared at the nest opening. What occured next happened so fast it seemed like a blur; but when I finally realized what was happening, I thought I was a goner. Fortunately, it was just a close call. From that moment on a shield was placed to minimize the mess and to

 

reduce the risk of some innocent passerby being struck by feces flying from seemingly out of nowhere.

It wasn't until April 22nd, that there were any signs that the young were trying to break from the nest. One chick was chisling away at the entrance with the tip of its already formidable bill. This went on intermittently until the early morning hours of April 24th. Two of the young had fledged by the time I had arrived that morning. The third fledged during the afternoon of the next day and all three were transferred to another facility, and had no problems eating on their own for the first time. The remaining chick apparently decided that it wasn't ready, and resealed the nest entrance. It wasn't until 2:00 p.m. on May 5th that it decided to fledge. It was soon removed, and after a brief physical, was placed with the rest of its siblings. There were no problems with feeding or interaction when it was reunited with the others.

I'm sure that most of us would agree we don't need any more problems than we already have; however this one turned out to be an interesting and rewarding experience. •

 


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