A relatively inquisitive and somewhat tame species, Mangrove Cuckoo has been perhaps unfairly labeled as "slow and stupid in its actions" (Clark 1905) or as "a lazy and foolish looking bird" (Wells 1902), although it does tend to be slow in its movements, more often walking and hopping within canopy vegetation than flying. Mangrove Cuckoos will cross fairly large gaps, especially in response to conspecific vocalizations. In mangrove forests, appears to forage primarily in the canopy (J. D. Lloyd, personal observations), where it walks and hops slowly from branch to branch, pausing occasionally to scan for prey by slowly rotating its head into often "grotesque angles" (Stiles and Skutch 1989). Prey are pursued by runs, hops, or, less often, sallying flights (Stiles and Skutch 1989). In vegetation types with an open understory, Mangrove Cuckoos may forage on the ground (McNair 1991).
Prey handling behavior is poorly documented. McNair (1991) described a Mangrove Cuckoo capturing and consuming a fairly large (10 cm) orthopteran over the span of approximately 4 minutes, during which time the bird removed and consumed the legs and beat the body of the insect vigorously against the ground before consuming it.
No information available, although radio marked birds in a population in southwestern Florida appear to occupy largely non-overlapping home ranges during the breeding season (J.D. Lloyd, unpublished data). Mangrove Cuckoos often respond aggressively to playback of conspecific vocalizations, which also suggests some degree of intraspecific territoriality (Frieze et al. 2012). It is unclear whether birds maintain year-round territories, as they rarely vocalize outside of the breeding season. However, individuals in Florida remain responsive to playback of conspecific vocalizations throughout the year (J.D. Lloyd, personal observations).
Mangrove Cuckoo presumably is socially monogamous with both parents engaging in parental care. Courtship feeding occurs but is not necessarily a precursor to copulation. During courtship feeding, the male perches on the upper back of the female and offers an item of food; if receptive, the female will rotate her head and raise her bill to receive the food item from the male (Langridge 1990). Copulatory behavior was described by McNair (1991) based on a single observation of a pair in Florida. Copulation appeared to be initiated by the female, who called repeatedly and engaged in "vigorous, rhythmic tail-pumping" for approximately 2 minutes before the male arrived and mounted her. The male grasped the female’s bill during the relatively brief (6 s) copulatory period.
Social and interspecific behavior
Mangrove Cuckoo occurs alone or in pairs; the duration of pair bonds is uncertain and it remains unclear whether pairs maintain association outside of the breeding season. There is little information on interspecific interactions. Lack (1976) reported that Vervain Hummingbirds (Mellisuga minima) defended their nest site against Mangrove Cuckoos, an observation that has been taken as evidence that cuckoos are at least occasional predators on the eggs and young of other species.
Little information available, but certainly vulnerable to both diurnal and nocturnal raptors; remains of Mangrove Cuckoo have been collected from roost sites of Aplomado Falcon (Falco femoralis) (Hector 1985) and Barn Owl (Tyto alba) (Olson et al. 1990).