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), ♀, 40567, juv. (July 9), ♂, 40568, testis 5 × 3 mm., 68.3 gm. (July 10), ♂, 40578, 59.5 gm. (July 11), and ♀, 40577, ova to 2 mm., brood patch, 65.2 gm. (July 11), all from 5 km. S Champotón; ♂, 40560, 43.6 gm. (July 20), ♀, 40562, brood patch, 55 gm. (July 21), sex? 40561, 64 gm. (July 21), and ♀, 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): ♀, 40579, 105 gm. (July 10), ♀, 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), 7½ km. W Escárcega; ♂, 40582, testis 10 × 5 mm., 169.1 gm. (July 27), and ♀, 40583, ovary inactive, 137.3 gm. (July 29), Pueblo Nuevo X-can; ♀, 40584, ovary 10 × 6 mm., 169.5 gm. (August 15), and sex? 40585, 148.9 gm. (August 16), 4 km. NNE Felipe Carrillo Puerto.