Macaw, Parrot and Parakeet may visit clay licks for more than a single reason

macaw clay lick
Red and Green Macaws (Ara chloropterus) on a clay lick in Southeast Peru. Photo Credit: Fernando Angulo.

Macaws, parrots, and parakeets that visit the clay licks in Southeast Peru are thought to eat clay to help them neutralize toxins consumed in their daily diets. Other macaws, parrots, and parakeets outside this region, and in other parts of the world, have similar diets but never eat clay nor visit clay licks. The possible reason(s) these birds chew and eat clay still remains largely unanswered.

In the 1990s when clay licks become a tourist attraction in Southeast Peru, biologist involved in the tourism industry started pilot studies to learn why these birds visit clay licks nearly every morning. After all “Why these birds visit a clay lick” was the most common question among visitors.

Biologist then thought that clay might help remove strong toxins occurring in the often unripe fruits macaws parrot and parakeets (and other animals) ingest on their daily diet.

parrot clay lick
Blue-headed Parrots  (Pionus menstrus) are a regular visitors to the clay licks in Southeast Peru. Photo Credit: Fernando Angulo.

The idea was that the high content of minerals in the clay binds with toxins consumed by these birds. The toxins and clay are then eliminated through bodily functions leaving the more digestible and nutritionally valuable food.

Support for this idea came from the fact that in parts of the world activated charcoal is used to absorb toxins or drugs ingested by humans. In fact, in parts of Peru, not far from where most clay licks occur, local people, eat or drink clay to alleviate stomach problems.

The problem with the idea of “clay as an absorbent of toxins” is that macaws, parrots, and parakeets in other parts of Amazonia, South America, and the world have similar diets but never eat soil or visit clay licks. Furthermore, species of macaw, parrot, and parakeets that consume more seeds, which potentially would have more toxins, do not use clay licks more than species that eat a greater proportion of flowers or fruit, which are thought to have less toxin content.

Interestingly, studies showed that the clay these birds consumed on the clay licks did not have higher levels of cation-exchange capacity (ability to absorb toxins) than that of areas outside the actual clay lick; thus these birds could not be using the clay to neutralize ingested toxins.

tambopata clay lick
Yellow-crowned Amazon (Amazona ochrocephala), Orange-cheeked Parrot (Pyrilia barrabandi), and Blue-headed Parrot are regular visitors at the Colpas. Photo Credit: Fernando Angulo.

A more recent explanation, which is in the process of being tested, is that sodium-rich clay helps macaws, parrots, and parakeets supplement their sodium-deficient diet.

Salt, which is made up of sodium and chloride, is an essential nutrient for animals. Salt is needed for the proper development and maintenance of bones, muscles, circulatory systems, and even the nervous systems. Salt is also an ideal carrier for a variety of essential traces of minerals like calcium, magnesium, phosphorus, and selenium.

Salt available in Amazonia decreases as one moves away from the Atlantic Ocean. This is because prevailing winds pick up and carry salt from the ocean onto Amazonia and, as it would be expected, a greater amount of salt is dropped in coastal areas than in areas further away from the ocean.

Western Amazonia, which is the most distant region from the Atlantic Ocean within Amazonia, is the most deficient in salt. Hence, the great need for sodium and other essential minerals in this region.

The lack of salt may help explain why macaw, parrots, parakeets, and other birds and mammals visit clay licks in Southeast Peru.

Again, the idea of “lack of salt” in western Amazonia makes physiological sense, but as the “clay as an absorbent of toxins” idea, it also has weaknesses. For instance, even in the region of western Amazonia, it is only in southeast Peru where macaws, parrots, and parakeets visit clay licks in such numbers and frequency. Western Amazonia is regarded as the area of Amazonia that runs adjacent to the foothill of the Andes of Colombia, Ecuador, Peru, and Bolivia, yet outside Southeast Peru, only a handful of clay licks exist and are visited by mostly parakeets and a few macaws.

blue-headed-macaw clay lick
The Blue-headed Macaw (Primolius coulonii) is rare in the region and visits only specific clay licks in small number. Photo Credit: Pantanal Bird Club.

Another possible explanation is that these birds, as well as other herbivorous animals, use the clay licks as a source of cobalamin, otherwise known as vitamin B12.

It looks like there is not a clear or a single reason why macaws, parrots, and parakeets visit clay licks. It may be for all of the reasons discussed above. Or just because clay at this locations is an element that goes well with their diets. It is like having a restaurant birds visit while in the region.

Macaws, parrots, and parakeets undergo seasonal movements tracking down food resources in Amazonia. This means clay licks are heavily used for only part of the year when these birds are in the region. The rest of the year clay licks are visited just by birds that stay in the region throughout the year.

References:

  • What’s Behind the Mysterious Behavior of Amazonian Macaws? https://www.wired.com/2014/01/tambopata-macaw-project/
  • Michael Kaspari, Stephen P. Yanoviak, and Robert Dudley. On the biogeography of salt limitation: A study of ant communities. Proc Natl Acad Sci U S A. 2008 Nov 18; 105(46): 17848–17851. Published online 2008 Nov 11.
  • Tambopata Macaw Project. http://macawproject.org/