Proposal (#31) to South American Classification Committee
Recognize Micrastur mintoni
Effect on South American CL: This proposal would add a newly described species to the list
Background: This cryptic species has been overlooked and confused with M. gilvicollis; see Whittaker (2002) for details.
New information: Whittaker (2002) discovered this species by noting an unfamiliar vocalization and tracking it down. This led to an analysis of specimens in Brazilian collections and some US collections and to an analysis of Micrastur recordings from all over Amazonia. He found that the new taxon differs strongly in voice (N = 42 recordings identified as mintoni) from other Micrastur, and is diagnosable (N = 53 specimens) from the most similar species, M. gilvicollis, in plumage pattern (tail barring; barring on underparts) and extent of supraorbital bare skin. See Whittaker (2002) for details and other differences that were statistically consistent but less than diagnostic. Although not emphasized by Whittaker, mintoni, found from east of the Madeira and south of the Amazon (as well, at least formerly in Atlantic forest of SE Brazil) appears to be allopatric with gilvicollis; although resolution of specimen sampling makes this less certain towards the Madeira, there seems to be a sharp replacement at the Amazon. Presumably mintoni and gilvicollis are sister taxa.
Recommendation: The plumage and morphological data presented by Whittaker strongly support mintoni as representing a diagnosable unit (subspecies or PSC species). Given the presumed allopatry of gilvicollis and mintoni, it all comes down to, in my opinion, voice in terms of species rank under BSC. Although I haven't compared actual recordings, the sonagrams presented by Whittaker show impressive differences between mintoni and gilvicollis, and even in the absence of playback trials, would provide support for species rank for mintoni, especially given the presumed importance of vocalizations in species recognition in these "hidden" micrasturs. I see no reason not to add M. mintoni to the list of species that we recognize.
WHITTAKER, A. 2002. A new species of forest-falcon (Falconidae: Micrastur) from southeastern Amazonia and the Atlantic rainforests of Brazil. Wilson Bulletin 114: 421-445.
Van Remsen, 26 June 2003
Comments from Zimmer: " I have seen and taped mintoni at several locations east of the Madeira, and can add assurances that the vocal differences (from gilvicollis) described in the paper are consistent and impressively distinct in the field. Just as an aside, I experienced this taxon for the first time at Alta Floresta (Mato Grosso, Brazil) in 1991. Ted Parker and I had our group on the road north of town pre-dawn, and a pair of these birds was duetting back and forth. Ted wasn't sure if it was a Micrastur or a frog, which should indicate just how different it was from typical gilvicollis! I was on my first trip to the Amazon, and had no experience with gilvicollis, so the difference in voice didn't mean anything to me at the time. Ted was amazed when we taped the birds in at first light and saw that they looked like gilvicollis. I've got a copy of his notes from that trip, and in the gilvicollis account he mentions the distinctiveness of the voice of the Alta Floresta birds and says "check this". Years later, when Andy Whittaker went to Caxiuana and heard/saw mintoni for the first time, he came back all excited and told me about a new species of forest-falcon that he had found. He played me the tape and I said "you know, I'm pretty sure that how gilvicollis at Alta Floresta sounds." I dug out my tape, and sure enough, it was a match. The morphological distinctions are sound too, but they are easily obscured by the amount of age variation (in both gilvicollis and mintoni) in specimens. I have no doubt that these are good species. It would be interesting to hear the Atlantic Forest birds (which are either very rare or already extinct), which Andy assumes are mintoni (probably so, but you never know)."
Comments from Schulenberg: " My vote: "Yes". I wish that Whittaker's paper had made more extensive inter-specific comparisons of vocalizations *other* than the territorial advertising song, but ... there it is."
Comments from Silva: "[YES.] Whittaker presented very good evidence (morphology and song) to give a species rank to mintoni."
Comments from Jaramillo: "YES. The paper looks solid, and Kevin's notes were helpful. Amazing that a raptor can be out there that was not recognized as being different for so long!
Comments from Nores: "[YES]. En este caso en particular yo estoy muy de acuerdo en que la diferencia de voces con M. gilvicollis son tan marcadas como para separar las especies."