Rhamphastos sulfuratus sulfuratus Lesson: Keel-billed Toucan.—This species was especially common west of Escárcega, where it was most often seen in small flocks of less than 10 birds. Presumably breeding had already occurred; four specimens had inactive gonads.
Specimens (7): ♀, 40589, 367.3 gm. (July 12), ♂, 40588, testis 8 × 3 mm., 414.5 gm. (July 14), ♀, 40590, ovary 11 mm., 347.4 gm. (July 15), ♂, 40591, testis 5 × 3 mm., 371 gm. (July 15), ♂, 40593, testis 6 × 3 mm., 422.2 gm. (July 16) and ♂, 40592, 401.5 gm. (July 16), 6-7½ km. W Escárcega; ♀, 40587, 395.5 gm. (July 28), Pueblo Nuevo X-can.
Piculus rubiginosus yucatanensis (Cabot): Red-capped Green Woodpecker.—Specimen (1): ♀, 40594, ovary inactive (7 × 4 mm.), extensive body molt, 67.7 gm. (August 17), 4 km. NNE Felipe Carrillo Puerto. Mallophaga: Penerirmus sp.
Drycopus lineatus similis (Lesson): Lineated Woodpecker.—Specimen (1): ♂, 40595, molting, 141.2 gm. (July 15), 7½ km. W Escárcega.
Centurus aurifrons dubius (Cabot): Golden-fronted Woodpecker.—The gonads were moderately enlarged in several of the specimens taken in the first half of July. The plumage was much worn in all specimens and some were in early stages of molt. Apparently the breeding season on the peninsula extends to at least mid-July. The specimen from Isla Cozumel is assigned to C. a. dubius, following the systematic treatment by Selander and Giller (1963).
Specimens (10): sex? 40602, 75.0 gm. (July 8), and ♀, 40601, ovary 6 × 3 mm. (enlarged oviduct), 76.4 gm. (July 10), 1 km. S Puerto Real, Isla del Carmen; ♂, 40599, testis 6 × 8 mm., 101.3 gm. (July 10), and ♂, 40600, 86.0 gm. (July 11), 5 km. S Champotón; ♂, 40603, testis 5 × 3 mm. (July 14), and ♀, 40604, ovary 6 × 4 mm. (ova to 1 mm.), brood patch (July 16), 7½ km. W Escárcega; sex? 40596, molting, much visceral fat, 79.0 gm. (July 22), Pisté; ♀, 40597, 73.7 gm. (July 28), Pueblo Nuevo X-can; ♀, 40598, 79.6 gm. (August 15), 4 km. NNE Felipe Carrillo Puerto; ♂, 40605, testis inactive, molting, much visceral fat (August 8), 3.5 km. N San Miguel, Isla Cozumel.
Centurus pygmaeus (Peters): Yucatán Woodpecker.—Paynter (1955a:166) reported evidence of breeding in this species on April 3 and May 23; a male having enlarged testes was taken on July 10.
Specimens (5): ♂, 40608, testis 6 × 4 mm. (July 10); ♀, 40607, 39.5 gm. (July 10), 5 km. S Champotón; ♂, 40609, testis inactive, 35.8 gm., moderate visceral fat (July 17), 1 km. N, 13 km. W Escárcega; ♀, 40606, ovary 6 × 4 mm. (inactive), 37.0 gm. (August 14), 4 km. NNE Felipe Carrillo Puerto; ♂, 40610, testis inactive, heavy visceral and subcutaneous fat, 41.6 gm., (August 10), 3½ km. N San Miguel, Isla Cozumel.
Phloeoceastes guatemalensis guatemalensis (Hartlaub): Guatemalan Ivory-billed Woodpecker.—Specimens (4): ♂, 40611, right testis 2 mm., left testis vestigial, 203.7 gm. (July 23), Pisté; 40612, sex? 212 gm., (July 28), and ♀, 40613, 218.1 gm. (July 30), Pueblo Nuevo X-can; ♀, 40614, 189.2 gm. (August 15), 4 km. NNE Felipe Carrillo Puerto.
Dendrocincla anabatina (Sclater): Tawny-winged Woodhewer.—Specimen (1): ♂, 40615, testis 2 × 1 mm., 35.7 gm., molting—5th primaries and middle pair of rectrices ensheathed (July 17), 1 km. N, 13 km. W Escárcega.