(July 15), 5 km. SW Escarcega; [Female], 40776, 61.3 gm. (July 21), Piste; [Female], 40777, imm., 63.4 gm. (July 20), 6 km. W Piste; [Male], 40779, testis 14 8 mm., brood patch, 68.5 gm. (July 30), and [Male], 40778, testis 13 11 mm., 71.5 gm. (July 28), Pueblo Nuevo X-can.

_Polioptila caerulea_ (Linnaeus): Blue-gray Gnatcatcher.--A fledgling taken at Piste was barely flying with remiges and rectrices ensheathed basally. Previous breeding records are for April 11 and 27 (Paynter, 1955a:231). A male taken on August 10 on Isla Cozumel had nearly completed molting into winter plumage.

Specimens (8): [Female], 40788, fledgling, 5.0 gm. (July 20), 6-1/2 km. W Piste; [Male], 40787, testis 2 1 mm., 5.6 gm. (July 21), [Male], 40785, juv., 5.8 gm. (July 22), and [Female], 40786, 5.6 gm. (July 22), Piste; [Female], 40791, juv., 5.6 gm. (August 8), [Male], 40790, juv., 5.8 gm. (August 8), [Female], 40789, 5.7 gm.

(August 9), and [Male], 40792, 5.3 gm., molting--7th primaries ensheathed (August 10), from {2-1/2}-{3-1/2} km. N San Miguel, Isla Cozumel.

_Polioptila albiloris_ Lawrence: White-lored Gnatcatcher.--This species was abundant in the arid scrub along the coast in the vicinity of Sisal.

Specimens (2): [Male], 40783, testis 1 mm., 6.2 gm. (August 7), 1-1/2 mi. S Sisal; [Male], 40784, testis 1 mm., 5.8 gm. starting to molt--1st and 2nd primaries ensheathed (August 10), 13 km. WSW Sisal.

_Ramphocaenus rufiventris_ (Bonaparte): Long-billed Gnatwren.--Specimen (1): [Female], 40793, imm. skull, 9.8 gm. (July 15), 7-1/2 km. W Escarcega.

_Cyclarhis gujanensis insularis_ Ridgway: Rufous-browed Pepper-shrike.

--Specimen (1): [Male], 40794, testis 2 mm., 37.8 gm., molting--4th primaries ensheathed (August 9), 4 km. N San Miguel, Isla Cozumel.

_Vireo bairdii_ (Ridgway): Cozumel Vireo.--Specimens (4): [Female], 40795, ovary inactive, 12.7 (August 8), [Male], 40796, testis 2 mm., 12.6 gm., molting--3rd and 4th primaries ensheathed (August 10), [Female], 40797, ovary inactive, 12.5 gm., molting--3rd primaries ensheathed (August 10), and [Male], 47098, imm., 13.1 gm. (August 10), from 2-1/2-3-1/2 km. N San Miguel, Isla Cozumel.

_Vireo pallens semiflavus_ (Salvin): Mangrove Vireo.--Paynter (1955a:236) noted breeding by this species from April 7 through June.

Specimens (2): [Female], 40800, ova to 3 mm., oviduct enlarged (July 8), Isla del Carmen; [Female], 40799, ovary inactive, 11.1 gm., molting--4th primaries ensheathed (August 2), Isla Mujeres.

_Vireo flavoviridus flavoviridus_ (Ca.s.sin): Yellow-green Vireo.--Paynter's (1955a:238) data indicate breeding in this species from late May through June; our records indicate that the species breeds at least through July.

Specimens (12): [Male], 40812, testis 10 4 mm., 17.1 gm., molting--1st, 2nd, and 3rd primaries ensheathed (July 17), and [Male], 40813, testis 7 4 mm., 18.2 gm. (July 17), 1 km. N, 13 km. W Escarcega; [Female], 40803, ovary 9 5 mm., ova to 1 mm., brood patch (July 21), [Male], 40805, testis 11 6 mm., 18.5 gm.

(July 21), [Male], 40804, 18 gm. (July 21), and [Female], 40802, ovary slightly enlarged, molting--2nd and 3rd primaries ensheathed (July 21), all from Piste; [Male], 40806, 17.5 gm., molting--1st primaries ensheathed (July 21), 6-1/2 km. W Piste; [Female], 40808, ovary 5 3 mm., 17.4 gm. (July 28), [Male], 40807, testis 5 3 mm., 17.7 gm., molting--3rd and 4th primaries ensheathed (July 28), [Male], 40809, testis 2 1 mm., 17.5 gm. (July 29), and [Male], 40810, testis 3 2 mm., 18.7 gm., molting--1st, 2nd, 3rd, and 4th primaries ensheathed (July 30), from Pueblo Nuevo X-can; [Male], 40811, testis 3 1 mm., 18.7 gm., molting--4th, 5th, and 6th primaries and middle pair of rectrices ensheathed (August 14), 4 km. NNE Felipe Carrillo Puerto. Mallophaga: _Philopterus_ sp.

July 21.

_Vireo magister_ (Lawrence): Yucatan Vireo.--Breeding on the peninsula has not been recorded previously. A male, beginning to molt, taken on August 10 on Isla Cozumel had enlarged testes, which were apparently regressing.

Specimens (3): [Female], 40814, ovary inactive, 17.7 gm. (August 2), Isla Mujeres; s.e.x? 40815, 19.5 gm. (August 9), and [Male], 40816, testis 6 3 mm., 20.2 gm., molting--1st, 2nd, and 3rd primaries ensheathed (August 10), 3-1/2 km. N San Miguel, Isla Cozumel.

_Cyanerpes cyaneus carneipes_ (Sclater): Blue Honeycreeper.--Paynter (1955a:283) collected specimens that were breeding in April. Testes were fully enlarged in two August-taken specimens and courtship rituals were observed in two pairs seen on August 3 at Puerto Juarez.

Specimens (3): [Male], 40817, 15.5 gm. (July 21), 6-1/2 km. W Piste; [Male], 40818, testis 12 6 mm., 12.1 gm. (August 3), 4 km.

WSW Puerto Juarez; [Male], 40819, testis 8 6 mm., 11.6 gm.

(August 14), 4 km. NNE Felipe Carrillo Puerto.

_Coereba flaveola caboti_ (Ridgway): Bananaquit.--Specimen (1): [Female], 40820, ovary inactive, 5 3 mm., 11.0 gm., molting--1st and 2nd primaries ensheathed, 3rd and 4th primaries missing (August 10), 3-1/2 km. N San Miguel, Isla Cozumel.

_Dendroica petechia rufivertex_ (Ridgway): Yellow (Golden) Warbler.

--Specimens (5): [Female], 40831, ovary inactive, 8.0 gm. (August 8), s.e.x?, 40832, imm. (fresh, first winter plumage), 10 gm. (August 8), [Female], 40830, ovary inactive, 10.0 gm., molting--4th and 5th primaries ensheathed (August 9), [Female], 40833, ovary inactive, 8.5 gm. (August 9), and [Female], 40834, ovary inactive, 7.8 gm. (August 10), all from 3-1/2-4 km. N San Miguel, Isla Cozumel.

_Dendroica petechia bryanti_ (Ridgway): Yellow (Mangrove) Warbler.-- Previous records of breeding by this species are available for March 29 and 30 and May 16 (Paynter, 1955a:247). Breeding apparently continues at least into July. An adult male with moderately enlarged testes (probably regressing) was taken on July 7 at Zacatel, Campeche, and a juvenile was obtained 13 km. WSW Sisal on August 10. The male at Zacatal was in mangroves alongside the ferry landing (for the ferry from Isla del Carmen) and seems to be the first specimen of this subspecies recorded for the state.

Specimens (7): [Male], 40829, testis 4 2 mm., 11.1 gm., molting--1st, 2nd, and 3rd primaries ensheathed (July 7), Zacatal, Campeche; [Male], 40823, imm., 10.0 gm. (August 9), [Male], 40824, testis 1 mm., 13.0 gm., molting--4th and 5th primaries and middle three rectrices ensheathed (August 9), [Male], 40826, juv., 10.1 gm. (August 10), [Male], 40827, imm. (fresh, first winter plumage), 10.2 gm. (August 10), s.e.x?, 40825, 10.3 gm. (August 10), and [Male], 40828, testis 2 mm., molting--7th, 8th, and 9th primaries, 2nd, and 3rd secondaries and outer pair of rectrices ensheathed (August 11), all from 13 km. WSW Sisal.

_Seiurus motacilla_ (Vieillot): Louisiana Waterthrush.--Our specimen, apparently an early migrant, was taken near the aguada at Rancho San Miguel.

Specimen (1): [Male], 40835, testis minute, 19.9 gm. (August 14), 4 km. NNE Felipe Carrillo Puerto.

_Tangavius aeneus aeneus_ (Wagler): Red-eyed Cowbird.--A male having enlarged testes taken on August 14 seems to be the first record of breeding in the species for the peninsula.

Specimens (2): [Male], 40838, testis 11 7 mm., 66.9 gm. (August 14), and [Female], 40839, ovary 6 mm., 60 gm. (August 15), 4 km.

NNE Felipe Carrillo Puerto.

_Ca.s.sidix mexica.n.u.s_ (Gmelin): Boat-tailed Grackle.--Specimen (1): [Male], 40840, 223.3 gm. (July 9), 1 km. SW Puerto Real, Isla del Carmen.

_Dives dives dives_ (Deppe): Sumichrast Blackbird.--This species previously has been known to breed in May (Paynter, 1955a:263). The specimens from July had moderately active ovaries.

Specimens (2): [Female], 40842, ovary 8 4 mm., 92 gm. (July 11), 5 km. SW Champoton; [Female], 40841, ovary 11 5 mm., 88.6 gm.

(July 21), Piste.

_Icterus prosthemelas_ (Strickland): Black-cowled Oriole.--Specimens (2): [Female], 40843, ovary 5 3 mm., 28.8 gm., molting--extensive body molt, 1st, 2nd, and 3rd primaries ensheathed (August 3), 4 km. WSW Puerto Juarez; [Male], 40844, testis 2 1 mm., 31.0 gm., molting 1st, 2nd, 3rd, and 4th primaries ensheathed (August 16), 4 km. NNE Felipe Carrillo Puerto.

_Icterus mesomelas_ (Wagler): Yellow-tailed Oriole.--Our specimens extend the known breeding season; previous records are for April and May (Paynter, 1955a:265).

Specimens (4): [Male], 40848, testis 11 5 mm. (July 14), 7-1/2 km. W Escarcega; [Male], 40846, juv. (rectrices and remiges ensheathed basally), 30.3 gm. (July 29), and [Male], 40847, testis 12 mm., 38.0 gm. (July 29), Pueblo Nuevo X-can; [Female], 40845, ovary 6 3 mm., 32.5 gm. (August 4), 4 km. WSW Puerto Juarez.

_Icterus auratus_ Bonaparte: Orange Oriole.--Paynter (1955a:266) reported breeding specimens taken in April and May. Two males taken in late July had fully enlarged testes.

Specimens (2): [Male], 40849, testis 10 6 mm., 32.5 gm. (July 28), Pueblo Nuevo X-can; [Male], 40850, testis 11 7 mm., 33.0 gm.

(July 30), 1-1/2 km. S, 1 km. E Pueblo Nuevo X-can.

_Icterus gularis_ (Wagler): Black-throated Oriole.--Breeding in this species was reported by Paynter (1955a:267) only for the month of April. Breeding was apparently nearing an end in late July at Piste, where several juveniles were taken. Adult males had moderately enlarged testes.

Specimens (8): [Male], 40858, testis 5 3 mm., 67.2 gm. (July 20), 6-1/2 km. W Piste; [Male], 40853, 59.0 gm. (July 21), [Female], 40851, imm., 49.9 gm. (July 21), [Male], 40852, 56.4 gm. (July 21), [Female], 40855, imm., 49.9 gm. (July 22), [Female], 40856, ovary inactive, 50.0 gm. (July 22), [Male], 40854, testis 6 4 mm., 63.8 gm. (July 22), and [Male], 40857, juv. (all rectrices and remiges ensheathed basally), 30.4 gm. (July 27), all from Piste.

_Icterus cucullatus_ Nelson: Hooded Oriole.--This species has not heretofore been recorded as breeding on Isla Cozumel; testes were nearly fully enlarged but probably regressing in the only specimen taken there. It had been banded (USF&WS no. 601-87003) on the island in 1961 as an adult. According to Paynter (1955a:269) there are no breeding records for this species on the mainland later than April, March 25 being the earliest date. The species was observed nesting on Isla del Carmen and adult males taken there and 5 km. S Champoton in early July were in full breeding condition.

Specimens (6): [Male], 40863, testis 11 7 mm., 26.3 gm. (July 8), [Female], 40864, 31.4 gm. (July 8), and [Male], 40862, testis 11 5 mm., 24.7 gm. (July 8), 1 km. SW Puerto Real, Isla del Carmen; [Male], 40860, 26.5 gm. (July 9), and [Male], 40861, testis 10 5 mm., 20.9 gm. (July 11); 5 km. S Champoton; [Male], 40859, testis 8 5 mm., molting--7th primaries ensheathed, 27.0 gm. (August 8), 3.5 km. N San Miguel, Isla Cozumel.

_Tanagra affinis affinis_ Lesson: Lesson Euphonia.--Specimens (2): [Female], 40866, 8.8 gm. (July 22), Piste; [Male], 40865, testis 3 2 mm., 10.0 gm. (August 3), 4 km. WSW (Aeropuerto) Puerto Juarez.

_Tanagra lauta lauta_ Bangs and Penard: Thick-billed Euphonia.--According to Paynter (1955a:272), the only breeding record previously available is that of a male having slightly enlarged testes on February 12. Males taken on July 15 and on August 14 had fully enlarged testes; the gonads of several other specimens were apparently regressing, two specimens had begun to molt, and juveniles were molting into first winter plumage.

Specimens (9): [Male], 40874, testis 7 4 mm. (July 15), and [Female], 40875, ova to 1 mm. (July 15), 7-1/2 km. W Escarcega; [Male], 40869, testis 6 4 mm., 14.5 gm. (August 14), [Male], 40870, testis 2 mm., 14.5 gm., molting--5th primaries ensheathed (August 14), [Male], 40867, imm., 12.6 gm. (August 14), [Female], 40868, imm., 14.4 gm. (August 14), [Male], 40871, testis 2 mm., 14.4 gm., molting--2nd, 3rd, and 4th primaries ensheathed (August 14), [Female], 40872, ovary granular, 7.8 gm. (August 14), and [Female], 40873, ovary granular, 13.0 gm. (August 15), all taken 4 km. NNE Felipe Carrillo Puerto.

_Thraupis abbas_ (Deppe): Yellow-winged Tanager.--Paynter (1955a:273) reported breeding in this species in late April and late June. Gonads in our specimens were moderately active.

Specimens (2): [Male], 40877, testis 6 4 mm., 43.0 gm., molting--1st and 2nd primaries ensheathed (July 15), 1 km. N, 13 km. W Escarcega; [Female] 40876, ovary 7 4 mm., (ova to 1 mm.), 42.1 gm. (July 29), Pueblo Nuevo X-can.

_Spindalis zena benedicti_ Ridgway: Stripe-headed Tanager.--Two males in advanced molt but with enlarged gonads were taken on August 9 and 10 and seem to be the first records indicating breeding in this species on Isla Cozumel.

Specimens (3): [Male], 40878, testis 9 7 mm., 32 gm., molting--5th primaries and middle pair of rectrices ensheathed (August 9), [Male], 40880, testis 5 3 mm., 30.0 gm., molting--3rd, 4th, 5th primaries and middle two pairs of restrices ensheathed (August 10), and [Female], 40879, ovary inactive, 28.1 gm., molting--remiges are new; secondary coverts ensheathed (August 10), 3-1/2 km. N San Miguel, Isla Cozumel.

_Piranga roseogularis_ (Cabot): Rose-throated Tanager.--Breeding has been previously recorded from March 17 through May 11 (Paynter, 1955a:276). Our only specimen, a male in advanced molt, had enlarged (regressing) testes.

Specimen (1): [Male], 40881, testis 7 5 mm., 24.2 gm., molting--4th and 5th primaries ensheathed (August 15), 4 km. NNE Felipe Carrillo Puerto.