Atlas Identification Challenges – American Coot vs. Common Gallinule
Dave Moore, Environment and Climate Change Canada
April 30, 2024
Figure 1. Adult American Coot and Common Gallinule
ID Challenges
Adults of these two species, when seen, are easily differentiated by bill colouration (gallinules have a red bill with yellow tip and face shield extending onto their forehead whereas coots have a white bill) and plumage (generally look for white feathers on gallinules) (Fig. 1). The identification challenges for these two species comes from their secretive nature: you are far more likely to hear these birds than see them. If you hear what sounds like someone throttling a chicken in the cattails, it is likely a coot or gallinule calling.
Both species, make a wide variety of complex ‘henlike’ sounds, including loud, harsh (sometimes explosive) clucks, barks and calls that grade into one another and are given in various combinations. There is a great deal of overlap in many of the calls that these birds make; however, a few calls are distinctive and make identification by sound possible. The Peterson Guide to Bird Sounds (link below) is an excellent resource for learning and differentiating Common Gallinule and American Coot calls (that terminology is adopted below).
One way to distinguish these species is through their long calls. The gallinule “long” or “whinney” call (a.k.a. the “wipeout” call) is a high, descending nasal series of notes (https://macaulaylibrary.org/asset/105422). Gallinules also give a sharp, nasal, squeaky, “keek” call (singly or in series) that is distinctive (https://macaulaylibrary.org/asset/26799)
Coot vocalizations are generally more grating and raspy than gallinule calls. The coot’s long call (https://macaulaylibrary.org/asset/2804) is a slow series of either grating “croaks” or nasal “wails” (or combination of both, in alternation); individual notes are generally longer and more drawn out relative to gallinule “whinney“ call components. The distinctive, raspy “croaks” that can comprise the coot’s long call can also be uttered singly, or repeated more slowly and with longer intervals between notes (i.e. speed can be variable, but it is the grating, regular nature of the call notes that is key – think of pulling your finger slowly along the teeth of a comb).
Coot vocalizations are generally more grating and raspy than gallinule calls. The coot’s long call is a slow series of either grating “croaks” or nasal “wails” (or combination of both, in alternation); individual notes are generally longer and more drawn out relative to gallinule “whinney“ call components. The distinctive, raspy “croaks” that can comprise the coot’s long call can also be uttered singly, or repeated more slowly and with longer intervals between notes (i.e. speed can be variable, but it is the grating, regular nature of the call notes that is key – think of pulling your finger slowly along the teeth of a comb).
The gallinule “long” or “whinney” call (a.k.a. the “wipeout” call) is a high, descending nasal series of notes:
Gallinules also give a sharp, nasal, squeaky, “keek” call (singly or in series) that is distinctive:
Other aids to identification
Caution should always be taken when relying on distribution to identify a species. However, Common Gallinules are generally restricted to breeding south of the Canadian Shield, whereas American Coots also breed in squares throughout the north of the province (Fig. 2).
Figure 2. Breeding Evidence maps for American Coot and Common Gallinule from Atlas-2 (2001-05)
If you are able to observe nestlings, the two species are easily differentiated. Coot young have orange or yellow feathers, primarily covering the neck, but often also present on the back and wings. Gallinule young lack this colouration (Fig. 3).
Figure 3. Young of American Coot and Common Gallinule
How to record?
For both species, visual confirmation is always preferred over calls alone, and with repeated visits to the site, you may end up seeing the bird. As a general rule, take a precautionary approach when identifying these two species by sound alone, and always include field notes describing the call to assist validation by the RC or provincial committee. If you are unsure of which species you’ve encountered, you should record your observation as “moorhen/coot/gallinule sp.”. This information is still valuable even if you are unable to assign it to the species level. To enter this generic code on your checklist submission form, click “show rarities” and click on “moorhen/coot/gallinule sp.”
Resources:
Peterson Field Guide To Bird Sounds: https://academy.allaboutbirds.org/peterson-field-guide-to-bird-sounds
British Trust for Ornithology, Develop Your Skills series – Identifying Coot and Moorhen; :https://www.bto.org/develop-your-skills/bird-identification/videos/identifying-coot-and-moorhen
References:
Bannor, B. K. and E. Kiviat (2020). Common Gallinule (Gallinula galeata), version 1.0. In Birds of the World (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.comgal1.01
Brisbin Jr., I. L. and T. B. Mowbray (2020). American Coot (Fulica americana), version 1.0. In Birds of the World (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.y00475.01