Russet-crowned motmot

The back of a perched russet-crowned Motmot

Russet-crowned motmots are relatively small motmots that measure 30.5 to 35.5 cm long and weigh 74 to 104 g.[4] Like most motmots, russet-crowned motmots are not sexually dimorphic in plumage.[3][10] However, females have shorter tail feathers (10 to 15 cm) than males (11 to 22 cm).[3] Russet-crowned motmots have a rufous crown and nape.[4] They have a green back and green wings with blue-green primary feathers.[4] Their chest is pale green with a black spot, and they have an even paler underbelly.[4] Russet-crowned motmots have a long blue tail with a bare section near the tip of the longest central feathers, which creates a dark racket-shaped tip.[4] Their black bills have a slightly serrated edge and curve downwards.[4] Like most motmots, russet-crowned motmots have a black eye-mask which is lined by blue & violet feathers.[4][10] They have reddish eyes and grey legs and feet.[4] Juveniles have brown eyes and duller plumage.[4] The four subspecies vary in morphology; in comparison to M.m. mexicanus, M.m. vanrossemi is paler, M.m. saturates is larger and darker, and M.m. castaneiceps has a darker chestnut crown and its black eye-mask is more extensive.[4]

The front of a perched russet-crowned motmot

The russet-crowned motmot produces a low "krrp", "krrup", or "kru, krr-up" which is strung together, making a longer call.[4] They can also produce a hollow "ook".[4] Mated pairs take part in call-and-response duets.[11]

Russet-crowned motmots feeds on large invertebrates (i.e. grasshoppers, etc.), fruits, and small vertebrates (i.e. snakes, lizards, etc.).[4][10][13][14] They have the typical feeding strategy of the Momotidae family known as "flycatching";[10] russet-crowned motmots perch on low branches and dart out to catch prey or bite fruit.[4][10][13] They return to their perches to eat their catch and they hit their live prey against branches before swallowing it.[10]

Russet-crowned motmots are socially monogamous birds.[3] Females and males pair up during the breeding season and they both care for the brood.[3] Labour is equally divided between the mating pair.[3][7][11]

Breeding season is between May and July, which is the wet season.[3][7] Russet-crowned motmots tend to breed once per year.[3][7] They lay one small clutch of 4–5 eggs per breeding season, which is typical for tropical birds.[3] The incubation period is between 15 and 20 days.[3][7] Both males and females feed the hatchlings and fledglings leave the nest after a total of 30 to 42 days.[3][7] Russet-crowned motmots have a 68% hatching success rate and a 56% fledgling success rate.[3] 83% of hatchlings will successfully fly out of the nest.[3] Most of the deaths happen during incubation and the predation of the brood is primarily by snake and iguanas.[3]

Russet-crowned motmots are burrow-nesting birds.[7] Each mating pair digs a tunnel that is 88 to 170 cm deep in an earthen, roadside, or river bank.[3][7] The tunnels are horizontally flat, they can curve and they have an egg chamber.[3][7] The tunnels are only for breeding[3] but the breeding sites are multi-purpose territories that the russet-crowned motmots use for foraging, roosting, etc.[6][11] These tunnels are very dependent on the quality of the substrate because they can get flooded or collapse if they are not built in a suitable area.[7] Good nesting sites are hard to find and they are limited by soil type.[6][7] Loam-textured soils which contain sand, silt and clay are the best substrates for russet-crowned motmots to nest in because they have better drainage, they are easier to excavate, and they offer better ventilation.[6][7] Since suitable nesting sites are scarce, russet-crowned motmots are strongly sedentary and will return to previous nesting grounds because they already know the quality, food sources, shelters, predators, and breeding performances of that site.[6][7][11]

Charre et al. suggest that the lifespan of a russet-crowned motmot is at least 11 years.[3][7] This estimate is not definitive because it is based on the recapturing of one individual 10 years later.[3][7]

Territory is very valuable to russet-crowned motmots because of the lack of suitable nesting areas.[6][7][11] As a result, Russet-crowned motmots they are very territorial.[6][7][11] However, Richard E. Tashian reported seeing russet-crowned motmots in flocks of birds including golden-fronted woodpeckers, white-throated Magpie-jay, coloured thrush, streak-backed oriole and coppery-tailed trogon in Guatemala.[14] This suggests that russet-crowned motmots defend their territories only against individuals of their species which is called infraspecific territoriality.[15] When there is an intruder, the russet-crowned motmot holds a leaf in its beak to display combative behaviour before chasing or fighting the intruder.[11] This territorial behaviour is performed year-round during the breeding and non-breeding season.[11] Both paired and unpaired males and females defend their territory.[11] Mating pairs will react differently towards male intruders and female intruders.[11] They are more aggressive towards a male intruder than a female intruder.[11] When a male intruder holds a leaf, the mating pair get closer to chase or fight him.[11] But when a female intruder holds a leaf, the mating pair holds a leaf as well to warn her.[11]

Russet-crowned motmots wave their tails side-to-side when they see a predator as an acknowledgment of their presence.[16]