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Parrot News5 September 2008 Wild parrots and their feeding habits in the Peruvian rainforestAlan Lee The Tambopata Macaw Project Over 20 species of parrot, including the endangered Blue-headed macaw, vulnerable Military macaw and near-threatened Amazonian parrotlet, have been recorded in south east Peru. Hundreds of individual parrots eat clay on exposed river banks, in what has been described as one of the most spectacular ornithological wonders of the bird world. It’s one of the best protected regions of the Amazon and so the perfect place to study parrots in the wild. The Tambopata Macaw Project has been hard at it since around 1990. I started my fieldwork under the project in 2006, with what I thought was a simple aim: counting parrots. It proved to be a difficult task – evidenced by the lack of abundance or density data for even the most widespread of South America’s parrot species. How does one count a family of birds whose members are mostly green through 30 meters of green leaves? Through a mixture of obstinacy, naivety and the desire to do what has not been done before, I persisted. Previous year round monitoring of the largest claylick in the world at the Tambopata Research Centre has shown that there are distinct seasonal patterns in the numbers of parrots visiting the claylick. Few birds are seen at the end of the wet season from March to June. From July to January the number of birds on the clay increases dramatically. The clay provides benefits through mineral supplementation (especially sodium – don’t tell them about how much is found in our supermarket foods, they might start migrating!). Clay also helps to adsorb dietary toxins, which are common in many tropical plants. Counts of birds in the forest around the lick revealed changes in parrot detection rates. If this change was due to the claylick being close or due to seasonal migrations through the area had yet to be properly answered a few years ago. After a year of walking over 1000km of trails at a site with a claylick and comparing results to a site with no claylick, bird density estimates pointed to there being no major regional migrations occurring in the region, but that parrots are detected in higher abundance for about a kilometre around a claylick at peak times of the year. Results were supported by radio-telemetry studies being undertaken by the WWF in the region. Still, bird numbers did seem to change from month to month and according to the types of forest we were looking at. Flying over the Amazon rainforest one sees a vast, unchanging, green carpet. But in that seemingly unchanging green are different types of forest with different plants that produce fruit and flower at different times of the year. Seasonal changes in parrot diet In order to understand these local movements better, this year our team started to look at parrot diet. Although other studies have already shown that parrots eat a wide range of the natural fruits and nuts available to them, little has been published on what they are eating when in South America’s biggest biome. If I thought just counting parrots was hard, finding them when they are eating is even harder. Parrots are a good example of not talking with your mouth full, so we have to find them by the bits they are dropping while they eat silently in the canopy. Our teams (Peruvian field leader, local assistants and international volunteers) have celebrations when we get more than five registrations in a day. Now I understand why some publications have been produced on isolated Scarlet macaw feeding events, and why a study over a similar period by imminent parrot biologist Katherine Renton in Costa Rica recorded only 15 food plants over 49 feeding bouts. Over the past seven months we have recorded about 388 feeding bouts on 63 plant species from 26 plant families, and also recorded feeding on insect galls and termites. It turns out there are flavours of the month for parrots and that they are big fans of eating local and seasonal – guess it helps reduce their carbon footprint! For instance, while Brazil-nuts may be a Christmas treat for us they are more of a New Year treat for parrots. The huge Brazil-nut trees are in full flower by January, when White-bellied parrot and Orange-cheeked parrots are feasting on the yellow, fleshy flowers. The flowers of the Symphonia globulifera (a tree locally known as Navidadcaspi or “Christmas-like” due to the abundant red flowers it produces) are also popular, despite there being a range of fruits and seeds available. Many trees produce their seeds and fruit during the wet season, and macaws and larger parrots breed at this time of year to make the most of the abundant food supplies. Macaws in particular like picking apart the seed pods of Jacaranda and tearing apart the very hard pods of trees related to the Brazil-nut tree. Once the young Brazil-nut pods start to appear in March and April, they quickly attract the attention of the large macaws, including Scarlet, Green-wing and Blue-and-gold, as each pod contains up to 20 succulent young nuts and they are probably a lot healthier than Easter eggs. Once the pods start to reach adult size around June, even the powerful beaks of the macaws can’t open them, although it doesn’t stop them trying. We have observed a couple of concerted efforts by Green-wing macaws on adult pods, that have either been totally unsuccessful, or that have opened up such a small hole that we wonder if it was really worth all the effort to get a tiny piece of nut. They were probably just having fun – maybe like trying to open a can of peaches without a can opener. The smaller parrots tend to go for softer seed pods – notably a small tree called Inga alba or Shimbillo, whose seeds resemble beans (they’re in the same family - Fabaceae). This family of tree is one of the most popular and we have found parrots feeding on 10 different species. On large trees with many pods we have seen Blue-headed parrots feeding for up to an hour for several days in a row on individual trees, making us wonder if they eat anything else during that time. We do not have much information on how long most birds feed for as we arrive at most events when they are already underway and the birds don’t like to eat with people below them. However, we have observed Black-capped conures feeding on Cecropia fruit, from which they were probably picking out the tiny seeds, for up to forty minutes at a time. A lot of this time is also spent looking around for danger as parakeets are targets for the several species of forest falcon that lurk among the vegetation awaiting an unwary bird. A popular forest fruit among much of the Tambopata wildlife are the Pseudolmedia spp, whose fruit first appear around May at the start of the dry season. The sweet red fruits are eaten by everything from toucans to monkeys to Mealy amazons. Mealy amazons get a head start on most other animals as they start to eat the fruits when they are young and green, but they also enjoy the juicy fruit when they are ripe. However, as food choice becomes more limited with the dry season, the clear favourite food starts attracting attention. The Wasai palm (Euterpe precatoria) fruits are so popular that we have recorded birds queuing up to get at them. On one occasion a Spix’s guan, a large turkey-like bird, sat patiently on a branch next to a palm where a Scarlet macaw was picking off the small round fruit. On another occasion a Blue-and-gold macaw flew off and was replaced by five Black-capped conures. Why this palm is so popular is a bit of a mystery. The seeds have a very thin layer of pulp that is targeted by a range of birds that generally discard the seed. Some large macaws do crack these open, but our observations show they prefer the pulp. Although it is a fairly common palm, there are more common species that contain more pulp and have larger seeds for which we have recorded very few feeding events. One tree that is definitely not rare, especially around the local farms in fields that are lying fallow, is the Balsa (Ochroma pyramidale). As the last fruits are being scavenged from the Wasai palms, the large white flowers of the Balsa are starting to appear. Having observed large influxes of birds to secondary habit where Balsa is most common, I enlisted the help of a fellow student, Peter Cowen, to examine how important secondary habitat is for parrot food supply during the dry season. Initial results seem to show that the fleshy petals are like vanilla ice-cream to the Severe (Chestnut-fronted) macaw, White-eyed conure and Cobalt-winged parakeets. Feeding events on balsa flowers or seeds by the larger macaws are uncommon. The larger macaws seem to be rare during the dry months and may be seeking out other scarce and isolated food resources. For instance, they have been observed cracking open the rock hard seeds of the Ironwood tree (Dipteryx micrantha) to get to the embryo inside. Conservation implications of parrot diet Although large scale clearing of the rainforest for soya, palm plantations and for the creation of grassland for cattle is devastating to the region’s biodiversity, small scale shifting agriculture (aka organic farming) can create habitat for small macaws and parakeets. Both Balsa and Cecropia are common in secondary forest. Luckily, in neither of these species are parrots in conflict with man. However, Brazil-nut harvest by local Peruvians is a major economic activity and previous research has shown that up to 10% of the pods on a Brazil nut tree can be damaged by macaws. This can be a serious source of conflict, and parrots and macaws are still shot and eaten locally. The popular Wasai palm is one of the species from which palm-heart can be obtained (you can try this on your pizza in the local town of Puerto Maldonado). It is a thin, hard and very straight palm that is also used extensively for local construction. As such, it is rare in patches of forest used by people. The seeds of the Ironwood tree are not only popular with macaws, but these trees are one of the most popular nesting tree species due to their natural cavities. The Ironwood is under threat from the timber industry as the hard wood makes good floors. It also makes good charcoal and as such is one of the most harvested trees in the region. Ironwood trees over 1200 years old have been recorded but they take less than an hour to fell with a chainsaw and have no protected status. Lessons for parrot owners? Most of the plants have been identified by famous Peruvian botanist, Percy Nuñez. Percy also helped James Gilardi with his PhD thesis in the nearby Manu during the early nineties where over 130 food species were recorded. Percy’s opinion is that parrots eat anything. While that remains to be seen, I wouldn’t be surprised. On one occasion I was collecting specimens of a vine that had been dropped by a Green-wing macaw. After I had placed the chewed seed pods on a sheet ready for a photo, I felt a burning sensation in my hand. Although only a small amount of latex from this member of the Euphorbiaceae family was on my hand, it was very irritated. Macaw version of a curry maybe? Almost all advice on parrot diet seems to warn against avocado and chocolate. We have not observed parrots feeding on members of cacao, but a local guide who was previously an assistant on the project has observed Severe macaw feeding on young avocado in his farm. Of course we don’t know what happened to the birds subsequently – it may not have been a happy ending. I have been unable to track down any original research that proves avocado is poisonous to macaws and it has made me realise how little parrot diet information is based on concrete evidence. A lot of dietary advice comes from the poultry industry, and chickens are very different birds from parrots. Apart from Brazil nuts, it will be a challenge to obtain the plant types
mentioned here for any UK parrot. On a more concrete note, we can see
that parrots do have a wide and varied diet in the wild, although what
is eaten also depends quite a bit on the species involved. However, they
do have clear favourites that they will choose to eat for lengthy periods
before moving onto the next seasonal fruit. As such, just because your
bird has not eaten something offered on one occasion does not mean that
it won’t be worth trying again at a later stage. At the very least
we may want to follow the example set by wild parrots ourselves: eat lots
of fibre and greens, eat organic, eat local and eat seasonal. About the author Alan Lee grew up in South Africa. He first travelled to Peru in 2002 where he joined the Tambopata Macaw Project as a volunteer. He is currently doing his PhD, on the impacts of claylicks on parrot abundance, at the Manchester Metropolitan University. Although a society member, he does not own any parrots. Information on his work can be found at www.macawmonitoring.com Selected References: BRIGHTSMITH, D. J. (2004) Effects of weather on parrot geophagy in Tambopata,
Peru. Wilson Bulletin, 116, 134-145.
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