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Parrot News25 May 2009 Green-wing macaws: A day in the life of a riverside claylick Alan Lee “Is 4:30 am really a good time to be watching macaws?” I wondered to myself as I struggled to find my blaring alarm clock beyond my mosquito net in the pitch black of a cloudy night in the Amazon rainforest. Still getting used to the early morning wake-up I struggled through to the reception area of the Piedras Biodiversity Station. There my companion for the day, Andy, was already awake and getting our data sheets and telescope ready for a morning of monitoring Green-winged macaws and up to 11 other species of parrots at a nearby claylick. Great to see that some people are so keen – but then who wouldn’t be when you’re about to witness an avian show that would be the avian equivalent of a Ben Elton Broadway hit? Only it’s a bit more serious. We were trying to understand one of South America’s largest and most widespread macaws: Green-wing macaws are the second largest of the seventeen macaw species after the Hyacinth macaw, weighing over 1.2 kg and measuring up to a meter from head to tail. They are widespread in captivity as they are socially interactive with both people and other parrots. They are found throughout South America in lowland Amazon rainforest and temperate deciduous forest, with a range of over 8 million square kilometres. Populations are generally healthy, but have been reduced in parts of their range due to over-harvesting for the pet trade. We have also observed hunting by woodcutters drifting their rafts of mahogany past the claylicks. These macaws have been the focus of few studies in their natural habitat and so little information exists regarding Green-wing macaw ecology. They are regarded as common in lowland Amazon rainforest, with density ranging from two to eight individuals per square kilometre. Like most of the macaws, Green-wing macaws eat unripe fruits and seeds, which may give them a competitive advantage over other frugivores, such as monkeys. They are known seed predators, particularly of trees belonging to the Brazil nut family. Nests are sometimes seen on cliffs in Bolivia, but in Peru they predominantly nest in natural cavities in ancient Ironwood trees, with the breeding season lasting from November to March. During this period large numbers are seen on claylicks, where birds descend in large multi-species flocks to consume clay along exposed river banks. Despite being one of the most common large species of parrot seen at claylicks across South America, few publications exist regarding the species social behaviour in the wild. So, here we were in the middle of Peru, November, start of the rainy season. Would the grey clouds dampen our spirits or would the rising Neotropical sun disperse them? That morning, our luck held. Andy and I arrived at the observation blind, a crude construction of mosquito net and palm leaves, as the grey skies begin to blush with the attention of the rising sun. Our morning was enlivened by Blue-headed parrots and Mealy amazons fighting for space on the claylick. Too quickly their self-allotted hour was up and the birds dispersed slowly into the surrounding trees. A few lone birds who arrived too late to feed waited forlornly for a second chance to go down, but were eventually put off by the menacing low form of a Yellow-headed vulture circling low over the canopy. Andy nudged me out of a hypnotic trance induced by the endless hum of insects and gurgling waters nearby, and pointed up over the river. I admired the long tailed form of the first pair of Green-winged macaws gliding in over the river. Their deep red plumage appeared to be glowing in the early morning sunlight. They swooped into a tall Tahuari tree about fifty meters upriver from the lick. I never fail to be surprised how such colourful birds can totally disappear from view in the shadows of rainforest foliage. I had to look carefully to spot their long tails pointing down from their perch, to make sure they had stayed and not disappeared out the other side of the tree. We could just make out the birds preening, an activity that takes up a lot of time in the early morning. Sometimes they would nuzzle up to each other and preen each other: allopreening. After twenty minutes the pair stopped their social bonding, heads up and vigilant. A rough call alerted us to who they had seen – the next pair of macaws flying into the area. The pair in the tree answered the call, and was joined by the new comers, who took up a position on the opposite side of the tree. They settled down and also start preening and allopreening. Cycles of resting, preening and greeting of newly arriving pairs continued for the next hour, until by mid-morning we were counting forty individuals grouped together in the largest trees around the claylick. We wondered if we could tell apart different aged couples: one sitting close together, quietly, aloof, interacting little with their neighbours as though they had seen it all before; while another pair played, hanging upside down and interacting in a way that reminded me of exuberant teenagers in love. Unlike colonies of seabirds during breeding season, where mating is observed often, we observed no mating around the claylick. During the three month period we conducted observations over the breeding season, we would see only one mating event – at a Scarlet macaw nest well away from the claylick. As numbers of birds build up over the course of the morning, it becomes harder to identify bonded pairs. Despite the number of birds in the area, aggressive interactions are rare among the birds high in the trees. This changes however, as the birds start to drift down towards the claylick and tension builds. Eventually, a critical number is reached in the area of the claylick so that one or two birds start to feel secure enough to approach the clay. They do this slowly, flying diagonally downwards from perch to perch, closer and closer, until one is in the vines hanging over a corner of the claylick. We watched one hanging upside down from the vines, looking around carefully before launching himself onto the steep bank. He didn’t tuck straight in, but continued to look around. But that crucial step had been taken and the rest of the flock took up the feeding cry. Within minutes the face of the clay was red with macaws. We were now counting over 80 individuals on and around the clay. Preening is forgotten about at this stage. The reason everyone has come is to eat clay. At this time of year certain sections are in high demand. Caves nearly two meters deep have been excavated out in the preferred layers of the soil, and we loose sight of macaws disappearing into these. There is some nervous aggressiveness early on, as the birds settle down and get comfortable amongst the close press of other birds. Watching closely one can make out individual dramas. A lone macaw lands on an empty section to the right of the main bustle. Another macaw flies up and aims to land alongside, but an unfriendly lunge frightens off the newcomer, in a manner that reminds me of a pretty girl seeing off uninvited attention at a bar. A braver admirer flies in and despite the lunge of the sharp beak lands warily nearby. After a moment she starts to bite at the clay, and he sidles up closer. The next warning lunge is half-hearted and he can attempt to feed on the clay. A fight to her left interrupts her feeding and she flies to another section of clay. Her admirer follows, this time joining her unchallenged. On another section of the clay, a peacefully feeding couple are displaced with a loud squawk by an aggressive individual sporting a stripe of missing feathers over her eye. The effect reminds me of the semi-shaved head of a punk. Indeed, the punk does not feed, but instead moves over to another feeding bird and lunges out aggressively. His priority does not seem to be clay, but rather a need to dominate those around him, a reminder that not all macaws are nice and friendly. Generally, few aggressive approaches give way to fights. Instead a corresponding degree of submission is displayed, with birds making way for new birds on the claylick, and a high degree of near neighbour tolerance displayed. Whether this is a trade off of ‘safety in numbers’ for the chance to assert oneself socially is still not clear at this stage. Although our aim was to follow individual macaws for as long as possible, the constant movement, displacements, and lack of identifying features make this task largely impossible. All too often all the birds take off together in a flush caused by either an approaching boat, an approaching bird of prey, or a mistaken alarm call. Following an individual in the resulting pandemonium is impossible; but watching a hundred macaws fly together in unison compensates amply, as the clicking of Andy’s camera would often remind me. Overall trends in behaviour can already be seen. On the claylick, it is clear that the primary purpose for landing on the clay is for clay consumption, with nearly 90% of observations actively including the consumption of soil. Vigilance continues to be prominent, and preening and resting are at much lower levels. Although no predator attacks were observed of birds on the clay, several different species of raptors were observed in the area of the claylick. At one stage we watch an Orange-breasted falcon (Falco deiroleucus) attacking a pair of much large Green-wing macaws in flight over the river. The macaws seemed surprised by the unexpected insolence and escaped unscathed. Our observations suggest implications for captive or caged birds. Although the social element to the claylick seems important, since birds rarely leave together in flocks, it also appears that a pair needs to have some space for social preening, bonding and resting. Birds in a caged environment may be less able to obtain respite from non-pair companion birds. A lack of a comfort zone may result in poor feather condition and secondary problems, for instance feather plucking or parasite infestation. On the other hand, since preening is higher in the morning at the onset of the social event at the claylick compared to around nests, solitary birds with no need to impress may also preen less with similar consequences. That there appears to be a threshold for feeding to commence with the number of macaws in the area has not been established previously. Conserving claylicks is essential for the social functioning of Green-wing macaw populations. Once numbers drop below a critical threshold, birds will be less likely to feed, less likely to interact, and so less likely to maintain a social hierarchy. In addition, anecdotal evidence suggests that macaws can form bonds that may help protect nesting birds against possible intruders, be they other macaws or predators. The conservation of macaw claylicks across south eastern Peru for the ongoing survival of one of the regions most iconic bird species needs to become a regional priority. As Andy and I wonder along the forest trail back to the lodge and the other members of our expeditions, quietly reflecting on the highlights of the mornings monitoring. I long for the day when the country’s current slogan ‘Peru: A mining country’ becomes ‘Peru: a place for parrots’. It’s a long way off, even though the later slogan is apt. A harsh cry draws our attention to a flock of ten macaws flying over the clearing and back to the depths of the forest. They are an inspiration to continue to help the conservation efforts of this forest frontier now threatened by not just by logging, but by far more sinister developments: a major highway, gas extraction and the construction of a giant hydroelectric dam. So here’s one for those macaws; long may they fly free.
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