Biology, Breeding, and Keeping of the Hyacinthine Macaw (Anodorhynchus hyacinthinus)

by Dr. Hubert LÜCKER, Dresden Published in German and English in Zoo - Pädagogik - Unterricht (Year 3, Volume III) Kassel, Germany in 1995

The Hyacinthine Macaw ((Anodorhynchus hyacinthinus) is the biggest and one of the most beautiful parrots in the world. Formerly its range of distribution included central Brazil, south of the Amazon river, from Pará through Minas Gerais and Bahia up to the Mato Grosso. Small populations occur in Paraguay and Bolivia, both of them adjacent to the Pantanal region. Nowadays the former big range of distribution has shrunk to the Pantanal area and a few birds here and there. There are some records of sightings of hyacinthines north of the Amazon, but they are disputed and not confirmed (ALDERTON, 199I). The natural habitat is the Pantanal biom, which is completely flooded for nearly 5 months. In that time only the so called cordilleras, low, long hills, on which the big trees grow, which the macaws use for breeding, are above water level. On the cordilleras groves of Acrocomia ssp. and Schelea ssp. are found. The nuts of those palms make the better part of the diet of the hyacinthine macaws (PITTMAN, 1993). According to the last survey approximately 3.000 - 4.000 birds exist in the Pantanal (REYNOLDS,1993). If those numbers turn out to be true, then the situation is not as bad as it was thought to be. However, according to other authors there may be only 1.000 birds left in the Pantanal (LOW,1990; PATZWAHL, 1989; ROTH, I988, 1989).

There are two main reasons for the rapid decline of the hyacinthine macaws: First of all, its beauty attracts poachers, who sell the birds on the illegal market for exorbitant prices. Obviously there are a lot of so called bird lovers, who will pay any price without questions in order to possess one or several of these parrots (LÜCKER, 1990). Secondly, habitat destruction is making rapid progress. A third threat is looming in the near future. In the north of the Pantanal, near the town of Poconé, goldmining occurs - together with related problems like mercury pollution. By word of mouth I learned that in the north of the Pantanal contamination of eggs of Caranchos Polyborus plancus) with mercury is already observed with increasing tendency. If the legal and illegal gold mining continues, the hyacinthines as well as all other animals will be threatened by mercury in the very near future. The latest research in Amazonia emphasises this threat (VOGT, 1994). In the gold-mining areas at the Rios Xingu, Madeira, and Tapajós, the rate of miscarrying and poisoning is extremely high.

It was high time to start a breeding project for Hyacinthine Macaws, even more so as the number of birds in zoos and bird-parks in Europe in 1989 was insufficient (LÜCKER, 1990a, 1991, 1992} and breeding a rare event. Also important was the collection of all data available about the biology of the species.

A) Nutrition

Hyacinthine Macaws have the biggest beaks of all parrots. They are not only remarkable in size but also in strength. With the lower mandible the hyacinthines have the strongest chisel of all parrots, which enables them to split extremely hard palm nuts like those from Acrocomia and Scheelea in two (YAMASHITA, 1993). During the splitting of nuts they are known to use tools, as was described by HOHENSTEIN (1987}. Therefore it is logical that the Hyacinthine Macaws are highly specialized feeders of palm nuts. Most of their diet consists of palm nuts. The diet also includes fruits, other nuts, vegetables as well as pieces of bark and leaves. However, it is difficult to find out if they really eat or just play with the bark and leaves. Highly specialized species are always vulnerable to changes in the environment, that influence the source of their specialization. In the case of the blue macaws this can be observed. Anodorhynchus glaucus is extinct, most probably because its only feeding palm (Butia yatay) has been eradicated in the process of clearing the land for cattle breeding (YAMASHITA, 1993). The Lear's Macaw (A. leari) is under extreme pressure, because again the lack of sufficient palms (Syagrus ssp.) forces the birds to fly long distances (up to 180 km) to find sufficient nuts (SEITRE, 1989). In the Pantanal there are still quite a good number of palm groves of both genera. However, as in the licuri palms the growth of new palms is disturbed. Cattle feed on the young saplings and destroy younger palms by trotting on them. Therefore it is time for the projects for the protection of the blue macaws in Brazil - and for both species, Lear's and Hyacinthine, they are working already.

For zoos and bird parks the crucial question is that of an adequate substitution of the palm nuts. These nuts contain a high percentage of oil. Therefore the diet of hyacinthines and other macaws must contain a high percentage of oil seeds like sunflowers, any kind of nuts, and coconuts. Additionally the macaws are fed on fruits and vegetables and once or twice a week on cooked meat or gristle.

This is important. If you look at a ripe fruit or nut in the tropical wild, you will hardly find one that is not inhabited by insect larvae - and those are eaten too by the macaws when eating the fruit/ nut. The amount of meat or gristle eaten is only small, but it is essential. In the breeding of curassows (Cracidae; Galliformes) it is well known that the diet must contain a high percentage of animal protein, if you want to breed them. Curassows are gatherers of fruits in the canopy of the tropical rainforest, and again the ripe fruits are infested with insect larvae - and in order to keep and breed the currassows it is essential to feed the birds in an aviary with a diet containing up to 15 % of animal protein (DELACOUR & AMADON; 1973).

In Dresden Zoo we looked for the food preference in the Hyacinthine Macaws. We offered the birds a mixture of fruits, vegetables, nuts, meat/gristle in pellets for dogs, and cereals, consisting of a mixture of sunflower seeds (41 %), wheat (29 %), peas (19 %), buckwheat (5 %), hemp seeds (2 %), and a mixture of different kinds of big millet seeds (4 %). The dog pellets contain 17 % animal protein, 8 % fat, and 3 % crude fibre.

The food was weighed before the mixture was offered to the macaws in the evening. The next morning the remains of all items were collected and weighed. Losses are negligible, as the fencing of every aviary is sparrow tight. There may be a little amount eaten by an occasional mouse, but these rodents are not common in the aviary.

The Hyacinthine Macaws eat preferably sweet fruits like apples, pears, kiwi, and bananas. From the offered amount (= 100 %) of a definite kind of fruit they eat on average per day :

- apple 79.7%
- pear 70.1%
- kiwi 78.4%
- banana 91.1%

Juicy and soft fruits like oranges are less favorite fruits:

- orange 30.6%
- plums 50.0%
- grapes 45.0%

The total amount of fruit offered per day is on average 300 g/ bird.

All vegetables are eaten:

- carrots 53.1%
- cucumber 27.0%
- tomato 16.0%
- paprika 28.8%

The total amount of vegetables offered per day is on the average 30 g/ bird. However, in the vegetables a closer look to the total amount per day shows that the birds eat very little. In the case of paprika and carrots one can often see that they take a piece into the beak, chew and chip it. The chips, some of them very finely chipped, fall to the bottom and are not eaten.

The ratio of fruit/ vegetables per day is approximately 10 : 1 (300 g fruit : 30g vegetables). That means, that the vegetables are only something like appetizers for the birds.

In nuts, cereals and pellets the situation is different:

- nuts 100 %
- pellets 40 %
- cereals 55 % of the daily offered amount are eaten.

The total amount of nuts, cereals, and pellets offered per day is on average 100 g/ bird. Normally all nuts are opened and the contents eaten. Only the shells are left. Approximately 30-50 % of the pellets are eaten. However, again as in the vegetables the birds can be observed chipping the pellets without eating them. From the offered cereal mixture approximately 50-60 % is eaten: Most of the sunflower seeds and little of the other cereals and the dried peas. The cereals can be sorted into oily seeds (sunflower, hemp) and starch seeds (wheat, buckwheat, peas, millet). The hyacinthines prefer to sort out the oily seeds, as would be expected in a specialized palm nut feeder. If we offer nuts (walnut, hazel, peanut, coconut) ad libitum, the amount of fruits and cereals eaten by the birds drops significantly. Like all macaws hyacinthine macaws tend to waste food. Therefore the total amount of food offered must be high.

Hyacinthine macaws show special behaviour in harvesting palm nuts (LÜCKER, 1995). The favourite palm nuts are covered by a fibrous ectocarp, which in Scheelea is a little sweet and sticky. The macaws have to rip it off in order to get at the nut itself. Sometimes the ectocarp sticks to the beak, so that the macaw has to clean it. HOHENSTEIN reports by word of mouth that in Paraguay hyacinthines like to eat the nuts after they passed through the intestines of cows. The cows digest only the ectocarp. The nuts are intact after the passage through the intestines. SCHMIDT (1994) reports the same from the Pantanal. He calls the cow the "fast-food shop for the macaws". I could observe, that hyacinthines even supply rodents with palm nuts by biting single nuts off a fruit cluster and dropping it on the ground. The rodents (agoutis) eat the ectocarp leaving the nuts with a shiny white shell on the dark floor. The hyacinthines, after dropping the whole nuts, fty to the floor and search for the white nuts without ectocarp and eat them (LÜCKER, 1995).

B) Keeping and breeding

Hyacinthine macaws live in pairs but can also be observed in small groups. Most remarkable is the observation (SCHMIDT, 1994), that during the measurements of chicks and eggs in an artificial nesting log in the Pantanal up to 19 macaws arrived after the first alarm calls of the breeding birds. All 19 birds started calling and harassing the researchers. This could be observed on a regular basis. Contrary to other macaw species the hyacinthines tend to fly in bigger groups, stay together for a longer time and even roost together over long periods of time. This led to the question if Hyacinthine Macaws have something like colony breeding. MARQUARDT {1992) tried to find out " ... more about the behavioral patterns of the Hyacinth Macaw" by means of setting up a colony breeding experiment. She brought 6.6 birds together and formed thus a colony in a big aviary. A pecking order established quickly. However, MARQUARDT obviously expected to increase the number of eggs immediately. After one bird died after an attack by a conspecific the experiment was declared failed. In the studbook (EEP, European breeding program for endangered species) we decided to pair hyacinth macaws in flocks as that is obviously the natural situation. In such flocks pair formation may be observed within hours or days after the introduction. You have to be careful, because a real pair may start fighting and chasing the other birds in the aviary. Chasing may become severe and even lead to the death of another bird. In the EEP the best breeding results can be observed in those facilities, who keep several pairs closely together. Under such conditions the number of eggs and chicks is far higher than in those participants that keep only single pairs. It is too early to make a statistical analysis, but under aviary conditions the birds tend to breed easier and on a more regular basis if several birds are kept close together, so that they can see and hear each other.

In the EEP breeding pairs are kept separated in aviaries, which should have at least 30 cu. metre volume. Nesting logs should be present. The incubation time in the Hyacinthine Macaws is 28-29 days. Normally the hen lays two eggs and broods from the first egg onward. The second is laid 2 days after the first. The chicks hatch with two days difference too. There is a tendency for the hyacinthines to breed only every second year, with the exception that neighbouring pairs tend to breed every year. The breeding is done by the female. The male feeds the female on the eggs as could be observed in Dortmund Zoo by means of a special device that enables a view into the nesting log. The male sits guard either in the entrance of the nest or somewhere close nearby. After hatching the female feeds the chick, a most remarkable view, when the gigantic beak is offered to the tiny chick (the weight at hatching is approximately 30 g). The chick grows rapidly and leaves the nest after 100 days. At that time it is fully feathered, the blue sometimes a little dull. It can be easily recognized by the size and colour of its beak, which is small and greyish. Normally only one chick hatches, the second one dies. However, in very few cases the hatching and successful raising of two chicks has been reported, but it is exceptional.

According to the guidelines in the EEP hand-rearing of Hyacinthine Macaws should only be tried if every other method fails, and it must be an exception. The reason is, that isolated hand-reared Hyacinthine Macaws become absolutely tame - and then it is difficult to breed them. Chicks stay with the parents for approximately 7-10 months after leaving the nest. We do not know if the neighbouring birds in the Pantanal are kin to each other. We also do not know at what time the young birds are chased away by their parents in the wild. There is a lot to do and fortunately there are now investigations on ecology and biology of the hyacinthines executed in the Pantanal. However, the information from captive and wild stock must be combined to achieve a complete overview on the biology of this beautiful and highly endangered bird. One problem is the low reproduction rate. As the Hyacinthine Macaw is near the top of the ecological pyramid in the Pantanal and obviously has few predators, the normal reproduction success can be low: The long living Hyacinthine Macaws belong to the k-type, and therefore are vulnerable to influences from the outside adding to the natural selection factors.

In the EEP the breeding results are promising. In 1989 the EEP stock started with 123 birds (41.35.47) (LÜCKER,1992). Only 6 birds were F1, the rest was wild-caught. The number increased to 296 (I22.116.58) at the end of 1993 with 57 birds in Fl/ F2. Therefore the first aim, to build up a self-sustaining population in zoos, birdparks, and with interested private owners, could be achieved within the next few years. There are more very hopeful signs: One big breeding unit in the Philippines breeds on a regular basis more than 45 birds/ year, and another breeding unit in the US counts more than 30 chicks every year. Compared with the anxious situation in the Spix's Macaw and Lear's Macaw the Hyacinthine Macaw population moves to the safer side.

Summary:

The endangered Hyacinthine Macaws (Anodorhynchus hyacinthinus) are specialized feeders of palm nuts. The nuts contain a high percentage of oil. In harvesting the single palm fruits from clusters of Scheelea and Acrocomia palms Hyacinthine Macaws show a remarkable cooperative behaviour with rodents. They prefer the nuts without the slightly sticky ectocarp, which is preferred by the rodents and also by cows. In zoos and birdparks the offered food must contain lots of nuts of any kind. The macaws eat fruit, preferably if it is not too soft and juicy. Vegetables are a minor part of the diet. It is essential to offer animal protein in order to substitute the insect larvae that infest ripe tropical fruits. Hyacinthine Macaws tend to live in groups. It may be that they even prefer to have short distances between neighbouring nests. This is emphazised in the EEP stock. The best breeding results occur in those participants, who keep several pairs closely together. Single pairs show a tendency to breed only every second year. Normally one chick hatches after 28 days of incubation. After 100 days the chick leaves the nest. Two chicks in one nest are a rare event. The situation of the Hyacinthine Macaw in captivity is improving. Within the next few years we may have achieved the first aim - a self- sustaining population in our zoos, bird-parks, and with private breeders.

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