Summer Birds From the Yucatan Peninsula Part 3

_Crotophaga ani_ Linnaeus: Smooth-billed Ani.--The female taken on Isla Cozumel had a slightly enlarged ovary and had been banded (USFWS band no. 524-96303) on the island in 1961 as an adult.

Specimen (1): [Female], 40500, ovary 11 7 mm., 86 gm., molting (August 4), 3-1/2 km. N San Miguel.

_Glaucidium brasilianum ridgwayi_ Sharpe: Streaked Pygmy Owl.--A female (40501) was taken by a local boy at Pueblo Nuevo X-can on July 29 weighed 62 gm. and the ovary (7 3 mm.) was inactive.

_Ciccaba virgata centralis_ Griscom: Squamulated Owl.--Our only specimen, a female (40502) weighing 288.7 gm. and having an inactive ovary (13 4 mm.), was taken at night on July 16 from a mist net stretched across a small trail 1 km. N, 13 km. W Escarcega.

_Nyctibius griseus mexica.n.u.s_ Nelson: Mexican Potoo.--One specimen was taken at night 7-1/2 km. W Escarcega where it was found sitting on the limb of a large dead tree. A light but steady rain was falling at the time. On the night of August 16 along a stretch of newly-constructed road 4-16 km. NNE Felipe Carrillo Puerto, 27 potoos were seen, their large and brilliant, amber-colored eyes first appearing in the headlights several hundred yards ahead of our vehicle. All of the birds were perched between 30 and 60 feet above the ground on dead limbs of large trees, and all were perched on the same side of the road facing the light of a full moon. None was less than 200 meters from the next; few flew at the approach of our vehicle. In addition to one specimen taken along the road, another was taken from a fence post in a _milpa_ on the same night. It was approached close enough to be shot with a 22 caliber pistol loaded with dust-shot. All specimens had thick layers of subcutaneous and visceral fat and their gonads were small and seemingly inactive.

Specimens (3): s.e.x? 40505 (July 13) 7-1/2 km. W Escarcega; [Female], 40504, ovary 13 4 mm. (inactive), 265 gm. (August 16), and [Male], 40503, testis 5 3 mm., 320.5 gm. (August 16) 4 km.

NNE Felipe Carrillo Puerto.

_Chordeiles acutipennis micromeris_ Oberholser: Trilling Nighthawk.--This species was common in the arid coastal scrub west of Sisal, where hundreds could be seen flying every evening. They were common also at Puerto Juarez, but uncommon at Felipe Carrillo Puerto.

Specimens (2): [Male], 40506, testis 5 3 mm., 57.3 gm. (August 1), 5 km. WSW Puerto Juarez; [Female], 40507, ovary 4 3 mm.

(inactive), 37.0 gm. (August 16), km. NNE Felipe Carrillo Puerto.

_Nyctidromus albicollis yucatanensis_ Nelson: Parauque.--This species was especially common in the vicinity of Felipe Carrillo Puerto and on Isla Cozumel, and was seen at every collecting locality. A flightless, juvenal female was obtained by local boys at Piste on July 21.

Therefore the reproduction period seems to be longer than Paynter's (1955a:141) data suggested.

Specimens (5): [Male], 40512, testis 7 3 mm., 75 gm. (July 10), 5 km. S Champoton; [Female], 40508, juv. (remiges and rectrices ensheathed basally), 44.2 gm. (July 21), Piste; s.e.x? 40510, 55.5 gm. (August 8), and [Male], 40509, testis 3 1 mm., 73.5 gm., molting--outermost two pairs of primaries ensheathed (August 10); 3-1/2 km. N San Miguel, Isla Cozumel; [Male], 40511, 72.9 gm.

(August 15), 4 km. NNE Felipe Carrillo Puerto.

_Caprimulgus salvini badius_ (Bangs and Peck): Salvin's Whip-poor-will.--My only record of this species is provided by a female (40513) taken 3-1/2 km. N San Miguel, Isla Cozumel, on August 8. The specimen weighed 58 grams, had an inactive ovary (6 4 mm.), and was molting (8th and 9th primaries ensheathed).

_Chateura vauxi gaumeri_ Lawrence: Vaux Swift.--This species was seen at almost every locality visited. The only specimens obtained were brought in by a boy at Pueblo Nuevo X-can on July 30; he said he captured them in his house. Two of them were adults and four were fully-feathered young-of-the-year.

Specimens (6): [Male], 40516, testis 4 2 mm., [Female], 40519, ovary inactive, [Male], 40514, juv., 12.6 gm., [Male], 40515, juv., [Female], 40517, juv., and [Female], 40518, juv. (July 30) Pueblo Nuevo X-can.

_Campylopterus curvipennis pampa_ (Lesson): Saber-wing.--A female (40522), shot 7-1/2, km. W Escarcega on July 16, seems to provide the first record of breeding (ovum 6 mm. in oviduct) by this species on the peninsula. A non-breeding female (40521) that weighed 5.0 gms. was taken 4 km. NNE Felipe Carrillo Puerto on August 14.

_Chlorostilbon canivetii canivetii_ (Lesson): Canivet Emerald.--This bird was seen at all localities at which we collected on the mainland.

Specimens (4): [Female], 40530, ovary moderately active, 3.0 gm.

(July 22), [Male], 40525, 2.1 gm. (July 23), and s.e.x? 40526, 2.9 gm. (July 25), Piste; [Female], 40529, ovary inactive, 2.4 gm.

(July 26), 3-1/2 km. N Piste.

_Chlorostilbon canivetii forificatus_ Ridgway: Canivet Emerald.--The specimen is slightly larger than those taken on the mainland and is clearly referable to _C. c. forificatus_, a subspecies endemic to Isla Cozumel.

Specimen (1): [Female], 40534, ovary inactive, 2.8 gm. (August 8), 3-1/2 km. N San Miguel, Isla Cozumel.

_Amazilia candida candida_ (Bourcier and Mulsant): White-bellied Emerald.--This species seemed to be the commonest hummingbird at most localities on the mainland. However, it was not seen along the coasts.

Specimens (5): [Male], 40535, testis 3 mm., 2.9 gm. (July 12), and [Male], 40536, testis 2 mm., 3.6 gm. (July 14), 7-1/2 km. W Escarcega; [Male], 40531, testis 2 mm., 4.3 gm. (July 28), [Male], 40532, 3.8 gm. (July 28), and [Female], 40533, ovary inactive, 3.9 gm. (July 29), Pueblo Nuevo X-can.

_Amazilia rutila_ (DeLattre): Cinnamomeous Hummingbird.--In addition to the two localities from which specimens were taken, several individuals were seen near the airstrip at Puerto Juarez.

Specimens (2): [Female], 40538, ovary inactive, 4.1 gm. (July 30), 1-1/2 km. S, 1 km. E Pueblo Nuevo X-can; [Male], 40539, testis 2 mm. (August 14), 4 km. NNE Felipe Carrillo Puerto.

_Amazilia yucatanensis_ (Cabot): Yucatan Hummingbird.--Many of these hummingbirds were seen among the coco palms on Isla del Carmen. A female taken on August 14 with a moderately enlarged ovary may indicate that the breeding season extends well into the summer.

Specimens (4): [Male], 40540, testis 2 mm., 4.7 gm. (July 7), [Female], 40541, ovary inactive, 3.0 gm. (July 8), and [Male], 40543, 3.0 gm. (July 8); 1 km. SW Puerto Real, Isla del Carmen; [Female], 40542, ovary 6 2 mm. (ova to 1 mm.), 2.9 gm. (August 14), 4 km. NNE Felipe Carrillo Puerto.

_Trogon citreolus melanocephala_ Gould: Citreoline Trogon.--This species was heard or seen at all localities where deciduous forest was present.

Specimens (7): [Female], 40557, ovary 14 8 mm. (ova to 2 mm.), brood patch, 72.5 gm. (July 16), and [Male], 40558, 66.5 gm. (July 16), 7-1/2 km. W Escarcega; [Male], 40553, 74.0 gm. (August 1), [Female], 40552, 74 gm. (August 1), [Female], 40554, ova to 3 mm.

(August 2), and [Male], 40555, 76.2 gm. (August 2), 4 km. WSW Puerto Juarez; [Female], 40556, 76.4 gm. (August 15), 4 km. NNE Felipe Carrillo Puerto.

_Chloroceryle americana septentrionalis_ (Sharpe): Green Kingfisher.--My only specimen is a male (40559) shot near a large aguada at Rancho San Miguel, 4 km. NNE Felipe Carrillo Puerto on August 16. The specimen weighed 40.5 gm.

_Ceryle torquata_ (Linnaeus): Ringed Kingfisher.--Paynter (1955a:154) noted that this "species has not been recorded from Yucatan but it is undoubtedly present, at least in the sheltered lagoon behind the barrier bar." A single individual was seen in one of these lagoons on August 9 and 10.

_Eumomota superciliosa superciliosa_ (Sandbach): Turquoise-browed Motmot.--On July 9 this species was nesting in a large "colony" 5 km. S Champoton, Campeche, in a large abandoned gravel pit having vertical banks about 10 feet high. The pit was an irregular semicircle with an approximate radius of 100 yards and was bordered by a road on one side and elsewhere by low scrub vegetation. The pit was one of several found in the area and formerly was used as a source of limestone gravel used in constructing the road between Champoton and Escarcega. The exposed limestone substratum was overlaid with chalky soil six to eight feet deep.

Motmots were nesting in burrows dug in the layer of surface soil. A total of 101 burrows seemed to be in use or to have been used in 1962.

Nine appeared to be unused and 24 burrows evidently were abandoned before they were finished. The depths of 12 burrows selected at random were 34, 32, 37, 25, 28, 44, 36, 36, 24, 37, 22, and 43 inches, and averaged 33.4 inches. In cross-section the burrows varied from round (three inches in diameter) to oval (three inches high and four inches wide). The inner ends of the burrows were enlarged with a depression in the floor, where the eggs were laid.

The long axes of most burrows were straight and perpendicular to the face of the bank in which they were dug; two burrows nevertheless were curved laterally, and one was U-shaped, having two entrances that opened about 12 inches apart.

Eggs and nestlings were found lying on the bare soil at the inner ends of the burrows; no nesting material was found.

The contents of 10 burrows that were excavated are summarized in Table 1. Three nests contained no eggs or young. One of these was freshly dug. The other two empty burrows apparently had been recently occupied by nestlings and contained the foul smelling remains of fecal material, hundreds of beetle wings, and other undigestible parts of insects. The manure was teeming with large fly larvae.

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 sh.e.l.ls.

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).

a.s.suming 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 Chichen-Itza; adults with enlarged gonads and brood patches and juveniles were taken at Piste as late as July 21.

Specimens (19): [Male], 40565, brood patch, 59.4 gm. (July 9), [Male], 40564, testis 8 4 mm., brood patch, 68.0 gm. (July 9), [Male], 40566, 74 gm. (July 9), [Female], 40567, juv. (July 9), [Male], 40568, testis 5 3 mm., 68.3 gm. (July 10), [Male], 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 Champoton; [Male], 40560, 43.6 gm. (July 20), [Female], 40562, brood patch, 55 gm. (July 21), s.e.x?

40561, 64 gm. (July 21), and [Female], 40563, juv. (July 22), Piste. Eight nestlings (40569-76) that were taken from burrows at 5 km. S Champoton 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.