Atitlan Grebe

Podilymbus gigas

Please send me photos and information on this species so that I can build up a more detailed database.

Known locations
This species was previously known only from Lake Atitlan in southern Guatemala, where it is extinct in its pure form.

There has been a lot of debate in recent years about the exact status of the grebes that are still found on Lake Atitlan. In 1989 Anne LaBastille announced that the Atitlan Grebe, or Poc as it known locally, was extinct. However, this was after having just recorded two pairs of them. The assumption was presumably that this was not a viable population and that they could not recover. Her book ‘Mama Poc’ makes interesting reading for anyone interested in the birds of the region. It is probably the most closely monitored and understood decline and extinction of any bird species. However, many people have wondered whether they are still present; for instance, it may not be known how long the individuals last seen by LaBastille could have lived, though a later study by Laura Hunter also led to the announcement of their extinction. Unfortunately, I have not yet had the chance to read any of her work. The problem is made more difficult by the fact that there are now Pied-billed Grebes on the lake. A trip report by Graham Speight mentions the confusion in the situation and describes how the warden was claiming that there were still 62 pairs of Atitlan Grebes on the lake in 1990. Apparently, according to Grebes of the World (which I have not had the chance to see) in 1986 an attempt was made to round up the remaining birds as part of a captive breeding program. During the round up 36 of the birds flew away. As the Atitlan Grebe was flightless, this implied that these birds were hybrids. Howell and Webb describe seeing a large grebe in May 1989, along with a smaller bird that clearly was a normal Pied-billed. They discuss whether there may have been hybridization between the two forms and that the original pure Atitlan Grebes may now be gone. They also raise doubts about whether they were ever a true species.
During my visits to the lake I tried to track down some of the people that worked with Anne LaBastille and Laura Hunter. Even amongst many of the people who worked on the project there was a difference of opinion, though this seemed mostly to arise because they were unfamiliar with the situation regarding the Pied-billed Grebe and they were still reporting the Poc to be present, because they were misidentifying the smaller species. Probably my most reliable contact was Edgar Bauer Jr (who runs the Posada Lodge Chuitinamit across the bay from Santiago, tel 232 8677). He and his father, with the same name, worked closely with LaBastille for many years and he was present when she made her last survey of the lake. He is adamant that there are no pure Atitlan Grebes on the lake anymore though he says that there may still be some hybrids.
I searched most of the main reedbeds on the western half of the lake. The only grebes I saw were near San Juan. Unfortunately, at the time I had not seen that any Pied-billed Grebes for awhile, so I found it difficult to comment on the condition of the birds I saw. From what I can gather, the Atitlan Grebe was bigger than Pied-billed Grebe, had a darker head, was flightless, had a bigger head and bill and kept its summer plumage of dark bill band and bib throughout the entire year. My lack of experience makes the size difficult for me to judge, but my rather poor photos show the grebes beside some Ruddy Ducks (which were a bit smaller) and some American Coots (a bit bigger). The bill size and shape is also hard to judge. It seems that the drawings in Peterson and Howell and Webb may be a bit of an exaggeration when you compare it with the photo of an Atitlan Grebe that was given to me by my guide Guillermo (it was taken by Anne LaBastille and I do not yet have permission to use it. I include it here with some trepidation in the hope that she will not mind it being used for non-profit purposes in a discussion of the species she worked so hard to protect. If anyone has her contact details, can they please send them to me so I can contact her directly). The birds I saw did not appear to have particularly dark heads and had a distinctly darker crown that was offset by a paler face, which is a Pied-billed feature. However, all the birds I saw were in full summer (alternate) plumage between the fourth and the sixth of January. According to ‘The Sibley Guide to Birds’, Pied-billed Grebes should only be in summer plumage between February and September, though he is talking about birds in North America and it may be different further south. I have seen Pied-billed Grebes in full summer plumage with stripy young in southern Honduras as late as early November, so this may be normal for the region.
I leave you to look at the photos and decide for yourselves. I would be interested in any comments from people who are more familiar with the species than I am.

This site has info and says it has the call of the Atitlan Grebe, but I could not play the recordings
www.loe.org/series/gap_in_nature/

‘Historic updates’ on the Atitlan grebe contain some good information. Seven pages of information presented as a case study for a school activity.
www.sciencecases.org

There is a lot of info in The Anne LaBastille papers, which are held at Cornell.
rmc.library.cornell.edu

One specimen is mentioned in the collection of the Natural History Museum of Los Angeles County
www.nhm.org/research



LaBastille, A. (1974) Ecology and management of the Atitlan Grebe, Lake Atitlan, Guatemala. Wildlife Monographs No. 37. Wildlife Society.

Hunter, L. A. (1988) Status of the endemic Atitlan Grebe of Guatemala: is it extinct? Condor, 90, 906-12.

Howell, S. N. G. and Webb, S. (1995) A guide to the birds of Mexico and Northern Central America. Oxford University Press.

LaBastille, A (1990) Mama Poc: an ecologists account of the extinction of a species. W. W. Norton and co.

Land, H. C. (1970) Birds of Guatemala. Livingston.