Part 7

TABLE 1. Contents of 10 burrows of Turquoise-browed Motmots.

Burrow Fresh Eggs Nestlings Post-fledgling 1 * 2 4 3 3 4 4 5 1 3 6 4 7 1 8 x 9 * 10 *

* Nothing. x Broken egg shells.

Three burrows contained nestlings; one had four young with pin feathers, one a chick fully feathered, and one three newly hatched young and one egg.

In burrow 2, three eggs had advanced embryos and one was infertile; in burrow 3, the eggs had small embryos; and in burrow 4, the eggs appeared fresh. Burrows 3 and 4 were occupied by adult birds that did not flush during the excavation of their burrows. They were easily caught by hand and later prepared as specimens. One was a male and the other a female; each had a brood patch.

Possibly females of this species raise more than one brood in a single nesting season, but I have no direct evidence of this. Such an hypothesis is suggested by the different stages of nestings found in the burrows. Moreover, there were more than twice as many burrows as motmots in the area. The largest number of individuals counted at any time near the colony was 20 adults (about an hour after sunrise). Assuming that all of these birds had mates, the maximum number of adults present could have numbered about 40.

There is another bit of evidence for double broods. Because of fouling of the burrow that accompanies the raising of a brood of young, it seems improbable that a burrow would be used immediately for a second nesting attempt. Consequently digging a second burrow would be necessary, if a second brood is raised.

Most of my observations are in keeping with Skutch's detailed report (1947) of the species in Central America. According to him, eggs are laid in April and May in Honduras and Guatamala, although he did not state that breeding does not occur in other months. The observations in Campeche in early July suggest that breeding can occur over an extended period; Paynter (1955a:158) found the species to be in various stages of reproductive activity in April on the peninsula.

Skutch suggested that the motmots he observed in Central America were solitary nesters, and nest in "groups" only where suitable nesting sites are scarce. In Campeche, many suitable, seemingly identical, but unused, nesting sites were available within a few hundred yards of the site of the actual nesting "colony." Moreover, most of the burrows were only a few feet apart and no agonistic behavior was witnessed. It seems that this motmot is characterized by colonial nesting habits in Campeche, even where abundant sites for individual nesting efforts are available.

The species was abundant around the cenotes at Chichén-Itzá; adults with enlarged gonads and brood patches and juveniles were taken at Pisté as late as July 21.

Specimens (19): , 40565, brood patch, 59.4 gm. (July 9), , 40564, testis 8 × 4 mm., brood patch, 68.0 gm. (July 9), , 40566, 74 gm. (July 9), [Female], 40567, juv. (July 9), , 40568, testis 5 × 3 mm., 68.3 gm. (July 10), , 40578, 59.5 gm. (July 11), and [Female], 40577, ova to 2 mm., brood patch, 65.2 gm. (July 11), all from 5 km. S Champotón; , 40560, 43.6 gm. (July 20), [Female], 40562, brood patch, 55 gm. (July 21), sex? 40561, 64 gm. (July 21), and [Female], 40563, juv. (July 22), Pisté. Eight nestlings (40569-76) that were taken from burrows at 5 km. S Champotón on July 11 had the following weights: 42.4 gm., 39.7 gm., 38.5 gm., 12.2 gm., 40.0 gm., 30.7 gm., 26.8 gm., 19.0 gm. Mallophaga: Philopterus sp., July 9.

Momotus momota lessonii Lesson: Blue-crowned Motmot.--For convenience, the specimens from 5 km. S Champotón are assigned to M. m. lessonii on the basis of measurements (wing 139 mm., tail 240 mm., culmen [from feathers] 41.0 mm.) taken on one specimen (40579), which are within the limits of the subspecies as described by Ridgway (1914). Two other specimens from that locality were prepared as skeletons and their weights are essentially the same as those Paynter (1955a) recorded for M. m. lessonii. According to Paynter, there is a southward clinal increase in size in this species between the smaller M. m. exiguus in the northern part of the peninsula and M. m. lessonii in the extreme southern part. A more extensive series of specimens from the vicinity of Champotón probably would reveal a population intermediate in size between the typical representatives of the two races.

Specimens (3): [Female], 40579, 105 gm. (July 10), [Female], 40581, 98.9 gm. (July 11), , 40580, 102.5 gm. (July 11), 5 km. S Champotón.

Pteroglossus torquatus erythrozonus Ridgway: Collared Aracari.--A male taken at Pueblo Nuevo X-can on July 27 and a female from 4 km. NNE Felipe Carrillo Puerto on August 15 had slightly enlarged gonads, which probably were regressing. Apparently these are the first indications of breeding activity for this species on the peninsula.

Specimens (5): , 40586, testis 4 × 2 mm., 155 gm. (July 16), 7-1/2 km. W Escárcega; , 40582, testis 10 × 5 mm., 169.1 gm. (July 27), and [Female], 40583, ovary inactive, 137.3 gm. (July 29), Pueblo Nuevo X-can; [Female], 40584, ovary 10 × 6 mm., 169.5 gm. (August 15), and sex? 40585, 148.9 gm. (August 16), 4 km. NNE Felipe Carrillo Puerto.

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): [Female], 40589, 367.3 gm. (July 12), , 40588, testis 8 × 3 mm., 414.5 gm. (July 14), [Female], 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), 6-7-1/2 km. W Escárcega; [Female], 40587, 395.5 gm. (July 28), Pueblo Nuevo X-can.

Piculus rubiginosus yucatanensis (Cabot): Red-capped Green Woodpecker.--Specimen (1): [Female], 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), 7-1/2 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 [Female], 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 [Female], 40604, ovary 6 × 4 mm. (ova to 1 mm.), brood patch (July 16), 7-1/2 km. W Escárcega; sex? 40596, molting, much visceral fat, 79.0 gm. (July 22), Pisté; [Female], 40597, 73.7 gm. (July 28), Pueblo Nuevo X-can; [Female], 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); [Female], 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; [Female], 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), 3-1/2 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 [Female], 40613, 218.1 gm. (July 30), Pueblo Nuevo X-can; [Female], 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.

Dendrocincla homochroa homochroa (Sclater): Ruddy Woodhewer.--May 20 seems to be the only previous date of record for breeding in this species (Paynter, 1955a:171); our specimen extends the known season nearly three months.

Specimen (1): [Female], 40616, ovary 13 × 6 mm. (ova to 2 mm.), brood patch, 35.1 gm. (August 16), 4 km. NNE Felipe Carrillo Puerto.

Sittasomus griseicapillus (Vieillot): Olivaceous Woodcreeper.-- Specimens (2): , 40617, juv., 11.2 gm. (July 26), Pisté; [Female], 40618, ovary inactive, 10.5 gm. (August 15), 4 km. NNE Felipe Carrillo Puerto.