Autor: Hanne van Bavel and Diego C. Rubiano Franco
Hand-rearing team: Diego C. Rubiano Franco, Laura Rìos Ortiz, Oliver Busse, Hanne van Bavel
Article German: Zucht der Rostbauchamazilie im Weltvogelpark Walsrode
Hummingbirds are a family of new world birds, containing about 328 recognized species that inhabit different habitats in South America and southern North America.
Most of these species are tiny - the smallest bird alive is in fact a hummingbird: the Bee Hummingbird, measuring 5 cm from head to tail and weighing less than 2 grams!
Hummingbirds are well known for their extensively iridescent plumage and their main food source: nectar.
Their bodies are adapted to their specific feeding habits: with their long, sometimes curved bill they can access nectar in flowering plants, and their hovering flight allows them to remain seemingly ‘motionless’ in the air while feeding. Hovering arises by extremely rapid wing movement: some species can flap their wings up to 80 times per second!
Hummingbirds are solitary birds, often aggressively defending nectar sources. As a result, male and female hummingbirds will only associate briefly to mate, and the female hummingbird will take care of the eggs and chicks on her own. Chicks are fed with small insects and nectar, and as they grow, the proportion of insects will diminish. In adult hummingbirds, insects only make out 10% of the diet.
Hummingbirds are rarely kept in zoos because of their specific needs. One of the better known species is the Amazilia Hummingbird (Amazilia amazilia), which occurs in Western Peru and Ecuador.
This species measures 9 to 11 cm and weighs about 5 g. Amazilia Hummingbirds have a green head and upper back, a rufous tail and belly and an iridescent throat ranging from golden to turquoise green. Their wings are black and their bill is mostly red. Males and females look very similar, but females usually look a little duller and have a larger black tip on their bill.
Amazilia Hummingbirds prefer semi-arid to arid habitats with scrubs, thorn forests and desert areas. They are also common in cultivations, parks and gardens, even within larger cities such as Lima. The species breeds all year round, with females usually laying two eggs in a cup-like nest consisting of plant wool, fibers and spider webs. After an incubation period of 16 days the almost naked chicks hatch, weighing approximately 0.5 grams.
Amazilia Hummingbirds have been bred in some institutions, but it remains very difficult to maintain a sustainable population in captivity. In 2011, Weltvogelpark Walsrode had the chance to start an Amazilia Hummingbird breeding project. This was a fantastic opportunity for us, but of course it needed much preparation! For our hummingbirds, we designed a room where the light cycle, air inflow, temperature and humidity are artificially controlled. This room is divided into three parts: a kitchen for food preparation, enclosures for habituation and a large room for the breeding aviaries. Each of our breeding aviaries gives the bird access to two lamps for sun bathing, one pot with a fruit fly culture, one feeding tube with nectar, and one bath. Plenty of sticks and plants are available for the birds to sit down and rest, doors in between the aviaries allow for males and females to be easily put together for mating.
On the 30th of October 2011 it was finally happening: 6 female and 5 male Amazilia Hummingbirds safely arrived at Weltvogelpark Walsrode! After the quarantine period, the birds were moved to their individual breeding aviaries. All of the birds responded very well to the transfers. One of our females even started building a nest right away, resulting in the first egg on the 8th of march 2012! This egg was followed by another two eggs on the 18th and 20th of march. Sadly these first eggs weren’t fertilized, probably due to some fertility problems of the male or the pair did not harmonize very well. Once we recognized this, the female was paired with another male, which resulted in a fertilized egg on the 15th of May! At that moment we were confronted with another problem: all of our birds were very young, and none of them had any breeding experience. This is probably the reason why the female didn’t incubate very well. As a result, the egg had to be put in an incubator. Obviously, this was not an optimal situation, but it was very fascinating to see an embryo develop in such a tiny egg. Unfortunately, the embryo died on the 10th day of development.
After a quiet period in June and July, we had another egg on the 15th of August 2012. Because the female didn´t incubate at all, this egg had to be put in an incubator as well. After five days it was clear that the egg was fertilized, and 11 days later the first hummingbird chick finally hatched in Weltvogelpark Walsrode! Although the chick made a hole in the shell on its own, it was not able to hatch without our help and it weighed only 0.37 grams! The chick was hand reared in an artificial nest placed in a separate incubator. Initially, it only received some water, but after 24 hours, when the yolk sack was completely absorbed, we started feeding nectar and flies. The chick was fed every 20 minutes from 8.00 am to 11.00 pm and was left to rest during the night. Although the chick was begging very actively during the first two days, it looked very weak on the third morning and died a few hours later.
It took some time before we had another chance to breed these beautiful birds, but in November, one of our females started laying again. We were able to monitor the breeding behavior by placing a camera above her nest. The female laid two fertilized eggs and incubated them perfectly. On the morning of December 8th, we were very happy to find one healthy looking chick in her nest! It hatched completely on its own on the 16th day of incubation. A few hours later it got even better: the second chick started hatching! This chick also hatched on its own, after only 15 days of incubation. The female took good care of both chicks. She was constantly catching flies to feed to her chicks and in between she was cleaning or incubating them. The chicks clearly received an enormous amount of flies, causing their crops to grow as big as their heads. Both chicks grew very fast and were begging actively. After a week, their eyes started opening and after 10 days the mother stopped incubating them during the night. Sadly, on the 12th day after hatching, one of the chicks got some food in its trachea when it was being fed by the mother. We couldn’t do anything, and the chick died within two minutes.
Fortunately, the other chick kept on growing and after a while it was sitting on the edge of the nest, curiously looking at the world around it. During this period we started feeding the chick with a feeding tube, so it would recognize feeding tubes after fledging. On the 7th of January 2013, the chick took its first flight and made a clumsy landing on the floor of the aviary. During the next days it became better and better at flying and it started feeding from a feeding tube on its own. A couple of days after fledging, the chick was separated from its mother and
Weltvogelpark Walsrode had its first fully grown hummingbird chick!
Two months after the first chick fledged, an egg was once again abandoned by its mother. The fertilized egg was put in our incubator, and on the 14th of March, a chick hatched after 15 days of incubation. Once again, we tried the best we could to hand rear this tiny bird, and this time our efforts paid off!
The chick was always begging actively and it grew very well. It only weighed 0.5 grams on day two, but its weight increased to 3.3 grams on day 15 and 4.9 grams on day 25! We fed it fruit flies soaked in isotonic water, supplemented with nectar. The amount of fruit flies increased every day: on the 3rd day it was fed 45 fruit flies throughout the day, and on the 15th day this amount had been increased to 445 fruit flies! After day 15 we started lowering the amount of fruit flies, since adult birds hardly need any insects. The amount of nectar was increased every day as well: 0.48 ml on the 3rd day, 5 ml on the 15th up to 8 ml on the 25th day. The chick fledged on April 4th 2013, 21 days after hatching. A few days later, when the chick was completely independent, it was moved to a small aviary, where it could practice its flying skills.
This chick wasn’t the end of our breeding success. In fact, five more chicks successfully hatched and fledged, from which three were raised by their mother. The young females seem to catch up on their breeding and rearing experience, so that 4 young were successfully parent reared!
At the moment of writing, there were 7 healthy chicks flying around in their individual aviaries! Weltvogelpark Walsrode is very proud of this accomplishment, and of course we hope our efforts to breed these little birds will keep paying off in the future.
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