IDENTIFICATION ARTICLES

Hawaiian, American and Common Coot - Identification, Distribution and Occurrence.

The Hawaiian Coot (Fulica alai) is an endemic species found only in the Hawaiian Islands and can be found on all the Main Islands from Ni'ihau to Hawai'i, excluding Kaho'olawe. Occasionally birds may wander up to the Northwest Hawaiian Islands but the species has never been recorded away from the Hawaiian archipelago. American Coot (Fulica americana) can be found across mainland North America and is an occasional, but rare, visitor to Hawai'i. Common (Eurasian) Coot (Fulica atra) is widespread across Europe and Asia and has been recorded from the Mariana Islands and is a candidate for vagrancy to Hawai'i. Photo: Hawaiian Coot, Kaua'i, Hawai'i, 1999. © Christian Melgar.

Taxonomy

Until 1993 the Hawaiian Coot was regarded as an island sub-species of American Coot, but was split by the AOU in that year and is now considered a full species on behavioural and plumage characteristics. Common Coot has always been considered a full species.

Distribution

Hawaiian Coot: This endemic species is found only in the Hawaiian Islands and can be found on all the Main Islands from Ni'ihau to Hawai'i, excluding Kaho'olawe. The bulk of the population occurs on O'ahu and Kaua'i. Numbers can fluctuate widely between 2500 and 4000 individuals Statewide, but in most years at least 3000 birds are present. In certain years large increases are noted, such as that on Kaua'i in 1996, 1997 and 1998 when over 800 birds could be observed at Hanalei NWR, Kaua'i alone (usually only 200 or so are present there) and 600+ at Kaua'i Lagoons, Kaua'i (usually only 120 or so present). It is not known where these "extra" birds came from and it is as much of a mystery where they went to in the following years, as no great influx was noted elsewhere after the birds had dispersed or left the Kaua'i sites.

Birds from Kaua'i will often migrate to Ni'ihau to nest during the summer months if there has been sufficient rainfall during the winter and early spring to fill the shallow playa lakes which can be found on this otherwise rather dry island. Birds are also presumed, although no confirming evidence is yet available, to migrate between the Main Islands during weather events, temperature fluctuations and nesting seasons. Considered an Endangered species, but numbers in the thousands..

American Coot: The nominate form Fulica a. americana is common and widespread across much of North America and S. Canada from SE Alaska east to Nova Scotia and south to the West Indies, Nicaragua and Costa Rica, and wintering south to Panama. The Handbook of Birds of the World (del Hoya, 1996) states that it also winters west to Hawaii, but this classification seems to be based on pre-species splitting, and the species should be regarded as no more than a vagrant to the State. The race F.a.Columbiana is present in Colombia and Northern Ecuador, with a marked increase in numbers in Colombia between October and April occurring, although the origins of these birds is not known. Nominate form extremely numerous and shot as a game bird, with over 80,000 shot in some years.

Common Coot: The nominate form Fulica atra atra is found in Europe, North Africa, the Azores, the Canaries and east through Central Asia to Japan and south to the Indian subcontinent and Sri Lanka, with birds wintering south to West and Northeast Africa, Southeast Asia and the Philippines. The form F.a. lugubris is found in Eastern Java and Northwest New Guinea. F.a.novaeguinea is found in central New Guinea and F.a.australis is found in Australia, Tasmania and New Zealand. The form australis is apparently dispersive and may account for records of birds seen in the lowlands of New Guinea. Estimates of population size in 1970 were that several European countries had populations in excess of 100,000 pairs and with a minimum NE European population of 646,000 during the winter. Many Australian States recorded populations of 130,00 or more.

Occurrence in Hawai'i and the Pacific

Hawaiian Coot is endemic and resident in the Hawaiian Islands, with only inter-island movements recorded. American Coot has been recorded occasionally from the Hawaiian Islands, although most records appear to have been before the species was split and some (many) records are dubious with incorrect identifications being made, as well as confusion with immature birds. Only one specimen has been obtained, a bird taken in 1919 and is kept at the Bishop Museum in Honolulu. The forthcoming Birds of North America account for Hawaiian Coot states that several were seen in 1977 on Kaua'i, four reported by DOFAW (Department of Forestry and Wildlife) in 1982, 13 in August 1983, 35 in January 1984, 11 in August 1984 and 5 in January 1985. As well as these 4 or 5 were reported independently at Aimakapa Pond in fall 1985 and 4 on Loko Waka Pond in October 1985. One was also reported at Aimakapa Pond in the winter of 1986-87 and one reported from Kelaia Pond, Maui in April 1987. The only reports since these have been singles at Aimakapa Pond, Hawai'i in January 1988, Kealia Pond in January of 1998 and one at Aimakapa Pond in November 1999. Although undoubtedly the species has occurred (most likely as an irruptive vagrant with most records deriving from one influx, ie. 1982-1985) some of the records would probably not hold up under close scrutiny. What can be said however is that even accepting all these records American Coot is a very rare visitor to the State, with just two records documented for the last 13 years. It should also be noted that many resident birders living in Hawai'i have not seen American Coot in Hawai'i at either the well-visited or more remote and inaccessible sites, whereas it seems a lot of visiting or holidaying birders record the species at the most visited and accessible sites! Common Coot has been recorded from the Mariana Islands and is a definite possibility as a future addition to the Hawai'i list.

Occurrence elsewhere outside of normal range

Hawaiian Coot has been recorded from the Northwest Hawaiian Islands on a few occasions, as far west as Kure Atoll, but has never been recorded outside of the Hawaiian Archipelago. American Coot has been recorded on a number of occasions from Europe with records from Britain (April 1996 and April 1999), Ireland (1981), Iceland (1969, 1971 (dead)), the Faroe Islands (1985) and the Azores (1971, 1988 and 2001) and birds occasionally wander north in the spring from the American nesting grounds and reach Newfoundland, Labrador, Franklin and S. Greenland. Common Coot has been recorded as an accidental vagrant/migrant in Alaska, Labrador, Newfoundland, Greenland, Iceland, Spitzbergen and the Faeroes.

Identification

All three species are rather similar, with adults being dark gray-black in coloration with lobed feet and pointed bills with frontal shields of varying size. Hawaiian and American Coots exhibit white undertail coverts, whereas Common Coot does not show this feature. Immatures are much paler gray and exhibit grayer bills and smaller frontal shields. In Hawaiian Coot at least the frontal shield/knob often appears to be the last plumage characteristic to change to adult plumage, resulting in birds with adult-like body plumage but under-developed shields/knobs, which can be a pitfall for the unwary.

Hawaiian Coots occasionally exhibit shield knobs which are not red or white, and these can vary from blue-gray to orange, to yellow to red and orange, and anywhere in between. Hybrids have been reported between Common Coot and Moorhen (Gallinula chloropus) and offspring show mixed characters. It is likely that a hybrid Hawaiian/American or Hawaiian/Common or American/Common may pass unnoticed amongst large groups of Coot and if the individuals were fertile then second or third generation hybrid offspring would almost certainly not be identified.

Hawaiian Coot is dark gray-black with white undertail coverts, which form an inverted "v" shape. The white undertail coverts can sometimes be obscured and hard to observe, especially when birds are swimming. The bill is white in adults and pale gray in immatures, with intermediate color shown by older immatures and sub-adults. The frontal shield has two color forms - pure white as seen in Figure 1. and with a large deep red-maroon knob as shown in Figure 2, (but also see above). The knob on both forms is large and bulbous, although it appears more so on white morphs, and appears to protrude above the forehead in most cases, whereas the knob is small in American Coot.. Birds exhibiting a red frontal knob usually also exhibit a dark band across the end of the bill (Figure 2). At a distance or in poor viewing it can be hard to differentiate between adult Hawaiian and American Coots but several features should be looked for to confirm identification of an American Coot in Hawai'i. The black feathering at the bill base is smooth and rounded like in American Coot, but is different to Common Coot (for which see below). Probably the most important feature to differentiate this species from American Coot (adults with red knobs) is the configuration of the knob and bill base: In Hawaiian the knob is large and extends DOWN to the bill base, thus there is no extension of the white from the bill up to the knob (Figure 2). On American the white from the bill extends UP to the small knob and thus a noticeable area of white is easily seen extending from the base of the bill (Figures 4 -6).

American Coot is very similar to Hawaiian Coot but often tends to show a slightly paler body with a darker head. This species also averages slightly larger, but there is overlap and this should not be used as an identification feature alone. The frontal knob of American Coot is usually red/maroon (Figures 3 - 6) but also occurs in white, especially in the Eastern States. Birds with red knobs, as in Hawaiian Coots, exhibit a dark band across the end of the bill (Figures 3 - 6). The black feathering at the bill base is smooth and rounded (cf. Common Coot). The configuration of the shield knob and the bill base is important in separating American and Hawaiian Coots (see Hawaiian Coot above).

Common Coot is like the other two species but is often darker in plumage and lacks the white undertail coverts. The identifying characteristic for separation from Hawaiian and American Coots is the shape of the black feathering at the bill base. Whereas on the other two species it is smooth and rounded on Common Coot the feathering forms a point which extends slightly onto the bill (Figures 7 and 8).

Hawaiian Coot (Fulica alai) Figures 1.(above left) and 2.(above right), Kaua'i, Hawai'i 1998 & 1999. American Coot (Fulica americana) Figure 3.(right), Cumbria, Britain 1999. Photos © Christian Melgar (Figs.1 & 2); © Gary Bellingham (Fig.3)

Figure 4. American Coot (Fulica americana), Kent, Britain 1996. Photo © Alan Clark.

Figure 5. American Coot (Fulica americana), Kent, Britain, 1996. Photo © Alan Clark.

Figure 6. American Coot (Fulica americana), Kent, Britain, 1996. Photo © Mike McDonnell.

Figure 7. Eurasian Coot (Fulica atra), West Sussex, Britain, January 2002. Photo © Christian Melgar. Note the point of black feathers at the upperside of the base of the bill and frontal shield. Also note the absence of white undertail coverts.

Figure 8. Eurasian Coot (Fulica atra), West Sussex, Britain, January 2002. Photo © Christian Melgar. Note the same features as in figure 7.

Calls

Although slightly different to one another calls are unlikely to be a good identification characteristic in separation of vagrant birds.

Hawaiian Coot - Chicken-like "keck-keck" and similar clucks and creaks.

American Coot - Loquacious, has a variety of cackling and clucking notes, often repeated. Alarm call of male "puhik" and of female "poouk". Aggressive male also gives an explosive "hic".

Common Coot - Single short "kow", "kowk", "kup" or a sharper "kick", sometimes "kick-kowp". Male also has a mechanical "p" or "ta" call and female a high, short falsetto "oeu".

Measurements

Hawaiian Coot : 39cm

American Coot : 34 - 43cm. Male 576 - 848 (742g); Female 427 - 628 (560g). Wingspan = 60 - 70cm.

Common Coot : 36 - 39cm. Nominate male 610 - 1200 (902g); Female 610 - 1159 (770g). Wingspan = 70 - 80cm.

Summary

With careful observation it is quite easy to separate Hawaiian and American Coots from each other, although to ensure record acceptance a thorough description should be taken and ideally photographs or video should be obtained. Although not yet recorded (by mid-2002), Common Coot is a very likely addition to the Hawaiian List, and is a species that could turn up on any of the Islands and at any body of water. Again photographs would be the ideal for provenance of the record.

References

del Hoyo, J. Ed. 1996. Handbook of the Birds of the World. Volume 3 - Hoatzins to Auks. Barcelona.

Littlewood, N. 1999. The American Coot in Cumbria from Birding World 12:4. Norfolk, England.

Pratt, H.D. 1987. Occurrence of the North American Coot (Fulica americana americana) in the Hawaiian islands, with a review of the taxonomy of the resident Hawaiian form. Elepaio 47: 25-28.

Pratt, H.D. , P. Bruner and D.G. Berrett. 1987. The Birds of Hawaii and the Tropical Pacific. Princeton.

Christian Melgar. Worthing, West Sussex. UK. December 2001.

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