Tuesday, 20 May 2014

A dietary check-up for parrots in the western Amazon

Posted by Alan Lee

In a recently published paper, Alan, Stu and others report on an intensive study of the diets of a range of parrots in Peru. Dietary data of this sort are rare – seldom are the resources/person-power available to accumulate the data, and studying diets is not always seen as a fashionable way to go about ecology. Here, Alan talks about the study, its making, and its findings.

Parrots have good manners – they don't tend to speak with their mouths full. That makes them a bit hard to find when foraging quietly in the upper canopy. Luckily, they are messy eaters, and fruit fall invariably leads the observer to something frugivorous, be it a Red-howler monkey (Alouatta seniculus), Spix's Guan (Penelope jacquacu), Curl-crested Aracari (Pteroglossus beauharnaesii) or one of the 20 odd species of parrot – if you happen to be looking for them in the lowland Amazon rainforests of Peru. Together with people from all walks of life, I registered birds eating food for over two years, amassing a data set of over 1500 encounters with foraging parrots. 

Aldo, Philip, and Percy test what the macaws have been eating (Photo A. Lee)

One of the first things we noticed was that these birds prefer to forage from the same individual trees – usually amongst the largest tree (adults, and at least at canopy level). For the sake of independent samples, many of these repeat encounters needed to be omitted – but they accounted for over 10% of all encounters. We would place foraging tape on trees marked when a foraging encounter had been recorded, and soon some of the more frequently walked trails were decorated with registrations. 

A foraging event, the left over breakfast: macaws cracked open and at the seeds from this noxious vine (Photo A. Lee)

To account for the fact that we may be missing birds foraging on smaller items, like small fruit and flowers, we also watched birds from canopy towers, as well as when floating down the river by boat to town from our study sites along the Tambopata River. Rather unsurprisingly given the difference in sizes of the parrots involved, we found that different parrots fed on different plant species and reproductive parts. For example, while all parrots fed on Brazil nut trees, large macaws with their powerful beaks went for the developing seed pods, while the smaller parrots fed on the flowers. All parrots loved the fruits and seeds of the Wasai palm.

While the colourful or endangered macaws
are most frequently photographed at
claylicks, its the little and common
Dusky-headed parakeets that
visit in greatest numbers.

(Photo A. Lee)

One of the main reasons we were recording foraging events was to document what plant parts were being consumed (e.g. fruit pulp or seeds) and whether the fruit were ripe or unripe. We were expecting that our records of surveys of the geophagy sites in the area (claylicks where birds would eat soil) should indicate those birds that eat more seeds and unripe food items should be those that eat more soil, if the theory held that the clay binds dietary toxins. This is because unripe fruit and seeds tend to have higher quantities of tannins and other things that make the unripe fruit taste unpleasant – at least to us. This is because the plants don't want to have their reproductive bits eaten after all.

Red-and-Green Macaws at a claylick
on the Los Amigos River (Photo A. Lee)

In addition to the fun task of watching parrots feasting, we also undertook the more onerous task of recording the fruiting status of 1800 individually marked trees every month. We did this to understand phenology patterns – to identify if there were any periods with little food availability that could perhaps drive the parrots to consume soil in the absence of food. Although there was a clear pattern of peak flowering and fruiting seasons, there was something fruiting of flowering throughout the year, especially if we concentrated only on the plant species the parrots preferred to forage on. So there is no evidence that these parrots eat soil due to bottlenecks in food availability.

We had previously worked out bird densities for the region by conducting line transects at multiple sites in the area (http://onlinelibrary.wiley.com/doi/10.1111/j.1744-7429.2011.00847.x/abstract), so we could calculate an estimate for the population of birds that were in the vicinity of a claylick i.e. the audience. What we found when we divided upper estimates of the numbers of birds feeding on the clay by the local population, was that the macaws – the parrots most famous for eating seeds and unripe fruit items – in fact did not consume more clay than expected. Surprisingly, it was the parakeets associated with secondary forests – Dusky-headed (Aratinga weddellii) and White-eyed parakeets (Psittacara leucophthalma) – that were represented on the claylicks more than expected. 

In the popular literature claylicks are associated with, and illustrated by, the large and colorful members of the parrot family - the macaws (Photo A. Lee)

Furthermore, our foraging encounters also suggested that these birds ate more flowers – specifically balsa flowers (Ochroma pyramidale) – than seeds. In addition, those species that were associated with terra-firme forests (White-bellied parrots Pionites leucogaster and Orange-cheeked parrots Pyrilia barrabandi) were observed less frequently on claylicks. 
Most publications investigating patterns of clay consumption or reasons for clay consumption from the Peruvian Amazon have concluded that they do it for the sodium. Our dietary study at least does not support the alternative hypothesis – that they do it to counter dietary toxins. 

The research has been funded by:


Friday, 2 May 2014

Our Sangihe and Talaud project takes off

Posted by Stuart Marsden and Hanom Bashari

First, I’m delighted to say that the Rainforest Trust and Loro Parque Fundacion have agreed to fund our project on Sangihe and Talaud. The project will be undertaken in partnership with Burung, the Indonesian BirdLife partner. The bulk of the work will be done by Rob Martin (currently at BirdLife in Cambridge), who will start an MPhil/PhD here at MMU in July, under the supervision of Stu, Elias Symeonakis (MMU), and Nigel Collar of BirdLife. Working alongside Rob will be Hanom Bashari of Burung. 

Above - The Sangihe endemic and Endangered Elegant Sunbird Aethopyga duyvenbodei (Photo: Hanom Bashari). Below - Nutmeg, which along with Cloves are a major source of income for the people of Sangihe and a major impact on the forest (Photo: Stu)

Stu has recently returned from a trip to Sangihe and Talaud, where I was accompanied and looked after by Hanom. We first spent some time at Burung’s headquarters in Bogor discussing the project with Agus Budi Utomo, Burung’s chief and Ria Saryanthi. I had the opportunity to give a presentation to Burung staff and local graduates about our work at MMU, and particularly our research on tropical frugivores inside and outside of protected areas.

Above - Another Sangihe endemic, the Sangihe Kingfisher (Photo: Hanom Bashari). Below - Forest gardens on Sangihe. It could be that with a bit of tweaking, some of these habitats might be important for some of the endemics (Photo: Stu)

It seemed to take an age to get to the forest on Sangihe. The terrain is incredibly steep – that is partly why forest remains there when it has given way to clove, nutmeg and coconut plantations elsewhere on the island. We started searching for the Cerulean Paradise Flycatcher at Mount Awu – in forest which was heavily degraded. We didn’t find the bird but there were 1-2 valleys which contained habitat that might be ‘nearly good enough’ for the species. In fact, this seems to be a possible theme for our research….how can small changes to the way people use the forest yield significant increases in an area’s suitability for birds? It may be that creating buffers of lesser-used habitat around streams might be a potential way forward.

Above - Cerulean Paradise-flycatcher Eutrichomyias rowleyi and Below Sangihe Shrike-thrush Colluricincla sanghirensis both Critically Endangered (Photos: Hanom Bashari)

Our main recce was at Sahendaruman, where we did see the flycatcher in incredibly steep valleys. There aren’t many birds in these forests – particularly, a lack of monarchs, fantails, white-eyes etc means that mixed species flocks do not seem to develop. A clamber up the steep valley sides took us to the ridge tops – where the interesting-looking Sangihe Shrike-thrush was seen, but no Bulbul and definitely no white-eye.

Ridge forest on Sangihe (Photo: Stu)
Then on to Talaud. This is a very different island, relatively low-lying and ‘non-volcanic’. I has a nice almost  ‘Caribbean-like feel to it. We didn’t have time to get to the primary forests in the island’s interior, where there may be lots of birds and maybe new discoveries to be made, but the garden-type habitats and forest fragments we did visit were birdy. Talaud Rail, Talaud Kingfisher and the ‘new’ pitta were seen, although the only bushhens I saw were five Rufous-tailed Waterhen Amaurornis moluccana. Parrots, including the ‘Sampiri’ (Red-and-blue Lory Eos histrio) were reasonably common and we saw at least two of the Tanygnathus and the racquet-tail Prioniturus platurus.

The endemic and Near-threatened Talaud Kingfisher Todiramphus enigma (Photo: Hanom Bashari)

We visited a Sampiri roost and interestingly, we got the chance to talk to Pak Zaka, a very nice and very knowledgeable parrot trapper-turned-conservationist. My first question was “Are lories rarer now than they were 20 years ago? (when he worked with Jon Riley and Jim Wardill of ‘Action Sampiri’). His answer was quite surprising and incisive. “It is odd…that 20 years ago there were lots of parrot trappers, and year after year there were lot of lories. Now, at a time when there are few trappers, there are few lories. The reason? There are so many chainsaws….people cutting down the big trees that the lories need for nesting. The lories have gone into the big forest in the interior”. 

Red-and-blue Lories Eos histrio - Endangered (Photo: Hanom Bashari)

Finally, I got to visit WCS’s Maleo project in NE Sulawesi and even got to release two baby Maleos. A couple of days searching for Sulawesi endemics at Mount Mahawu and Dumoga Bone NP yielded Scaly-breasted Kingfisher, Rufous-throated Flycatcher, Maroon-chinned fruit dove, some nice owls, Blue-eyed Rail, and several other Wallacean treats.

The Sangihe Hanging-parrot Loriculus catamene is Near-threatened (Photo: Hanom Bashari)

A big thanks to all those kind folk we met along the way. 

Our project on Sangihe and Talaud is sponsored by