Until very recently, identification of wood-rails in the Turrialba area was a simple matter. There was only one candidate, the Gray-necked Wood-Rail (Aramides cajaneus) because the only other wood-rail in Costa Rica was the Rufous-necked Wood-Rail (Aramides axillaris), a rare species pretty much restricted to mangroves in the Gulf of Nicoya in the north-west. The names described the difference between the two very adequately for identification purposes.
However, recent taxonomic changes now bring a certain amount of confusion. The Gray-necked Wood-Rail (cajaneus) has been renamed, in English, the Gray-cowled Wood-Rail (still Aramides cajaneus) in most parts of the country, but the population in the northern Caribbean region has been given the status of species under the English name of Russet-naped Wood-Rail and the scientific name Aramides albiventris. Albiventris refers to a white belly-stripe not found on cajaneus.
Unfortunately for birders here in our region, many wood-rails here show a distinctly “russet nape” rather than a “gray cowl”. A cowl is really just a hood, and it seems to me that it serves as a good distinction between cajaneus and axillaris, but not between cajaneus and albiventris. At the same time, the Gray-cowled Wood-Rail has a dark brown nape The line of demarcation for this species between northern Caribbean and southern Caribbean has not been clearly defined and it is wise to make careful observation notes or obtain a good photograph. The voice of albiventris is said to be quite different from that of cajaneus, and, given the considerable plumage variations, may turn out be the best distinction. I’m going to go with cajaneus for our area unless I see that belly stripe or hear a voice that is new to me.
How about this pair, found by John Beer on the Río Reventazón at Peralta?
Or these, also found by John, at CATIE in Turrialba?
The 1st image is of a White-throated Crake.