Amazilia tzacatl
rufous-tailed hummingbird

Rufous-tailed hummingbirds live primarily in central-east, possibly northeast Mexico to central Panama. The northernmost populations most likely migrate to the Pacific and Caribbean coast of Mexico for the winter months (Guerrero and Yucatan). The migratory patterns of rufous-tailed hummingbirds in other parts of Central America are unknown. However, seasonal movements occur from Colombia through Ecuador. Also, several individuals of this species have been recorded in southern Texas in the summer and autumn. (del Hoyo, et al., 1999)

Rufous-tailed hummingbirds are found primarily on the edges of humid evergreen forest, banana or coffee plantations, human habitations, and clearings. These birds are not usually found inside the dense forest but often in second growth and semi-open areas. These thicket-rich regions are found in South America and are in gallery forest and montane zones. The elevation at which these birds occur vares from region to region. Their altitudinal distribution is correlated with the flowering periods of food plants. In Costa Rica and Panama through the subtropical belt, rufous-tailed hummingbirds are found in lower montane zones, from sea-level up to 1200 m. In Colombia and the islands of Panama their habitat consists of primary forest as well as bushy coastal habitats, even beaches. In the Andes, the hummingbirds can be found up to 2500 m, occasionally even higher. Some races in southwest Colombia range from the lowlands into the subtropical zone with wet, open forest up to 2500 m. (del Hoyo, et al., 1999; Jackson, et al., 2002)

Males and female the rufous-tailed hummingbirds differ slightly in physical appearance. The males are larger, weighing 5.5 g. Male rufous-tailed hummingbirds also have longer bodies. The maximum length of a male rufous-tailed hummingbird is about 11 cm. They have a straight bill, which is medium sized, fleshy red with a dark tip, and an upper mandible that is blackish. The upper parts of the male's body, the flanks and belly, are golden green to bronze-green. The throat is a glittering golden green and sometimes has a turquoise gleam in certain light. The belly is ashy gray to grayish-brown. The tail has traces of bronze-green and copper.

Female rufous-tailed hummingbirds are smaller than the males and have slightly different coloration. Females have a mass of around 5.2 g and their body length is usually about 8 cm. There is a grayish sub-terminal bar on the throat feathers and they have a white belly.

Immature rufous-tailed hummingbirds are darker and grayish towards the belly. The feather-edgings on the face and crown often have a bronzy edge. The upper mandible of younger individuals is often black.

The hummingbirds do differ from race to race. The handleyi race is larger and heavier than the average rufous-tailed hummingbird. It is also a slightly darker bronze-green. The fuscicaudata race is smaller than an average rufous-tailed hummingbird. The jucunda race has a longer bill in relation to its size with narrow margins in the outer rectrices.

The average wingspan for all hummingbirds is somewhere between 2 and 2.4 cm. The males often have larger wingspans than females. (del Hoyo, et al., 1999; Ridgway, 1892; Stiles and Skutch, 1989)

Hummingbirds have one of the highest basal metabolic rates of any birds due to their very small size, their type of flight, and the amount energy needed to sustain their flight. The average hummingbird metabolic rate is 1600Kcal/kg/day. (Ritchison, 2003)

Rufous-tailed hummingbirds may nest in loose colonies. They have been observed stealing nest materials from their neighbors. (del Hoyo, et al., 1999)

Rufous-tailed hummingbirds are polygynous. Hummingbirds only have contact with the opposite sex for a few moments during fertilization. Males are very territorial and often claim an area of flowers as their own during mating season. (Baker, 2003)

Breeding occurs at different times of the year throughout their range. In the northern parts of Central America, nesting can occur from December through September. In Mexico, breeding season is from March through August. In Costa Rica, breeding is guided by the dry season and peaks in January through May. Along the Pacific slope, breeding occurs from May through November. Along the Caribbean slope breeding occurs in October through January. Breeding in South America and Panama occurs in January through April.

Nesting is fairly specialized for rufous-tailed hummingbirds. Their favorite sites to build nests are on horizontal branches in smaller trees and shrubs. The nests are usually 2 to 5 meters off the ground. Sometimes the nests are built in the fork of a branch.

Materials used for nest construction include plant down, yellowish-brown to grayish-brown fibers, cobwebs and pieces of dead leaves. The exterior of their nest is decorated heavily with bits of lichen and sometimes moss. These materials are usually formed into a compact cup nest. If a nest is destroyed or lost, construction of a new nest may start within a week. (del Hoyo, et al., 1999; Stiles and Skutch, 1989)

Females usually lay two eggs per clutch. Incubation lasts 15 to 16 days. Young leave the nest when they are between 18 and 22 days old. Young rufous-tailed hummingbirds are fed by the female for 58 days. (Skutch, 1976)

Incubation lasts 15 to 16 days and is only done by the female. Young leave the nest when they are between 18 and 22 days old. Once hummingbirds fledge, they wait for their parents in a distinct spot that is usually not far from the nest. They do not follow their parents around as they forage, but rather wait to recieve food. Once the female fills her crop with nectar, small insects and spiders she returns to feed her young. The young rufous-tailed hummingbirds are fed this way for 58 days. Males do not provide any parental care. (del Hoyo, et al., 1999; Skutch, 1976)

Although there is little research on the lifespans of hummingbirds, researchers estimate an average hummingbird lives 3 to 5 years. The longest recorded living female was a broad-tailed hummingbird, found in Colorado at age 12. In captivity, they can survive about 10 years. ("All About Hummingbirds", 2002; "About Hummingbirds", Date Unknown)

These birds can be highly aggressive and territorial at rich clumps of flowers. Intruders such as larger hummingbirds, butterflies, and euglossine bees are sometimes attacked with a diving flight. (Jackson, et al., 2002; Stiles and Skutch, 1989)

Rufous-tailed hummingbirds may form very loose nesting colonies. They are generally more sedentary in humid regions and are diurnal or crepuscular, depending on the region. (del Hoyo, et al., 1999)

Rufous-tailed hummingbirds (along with many other hummingbird species) have such high metabolic rates that they often go into torpor during the night to conserve energy. (Baker, 2003)

Hummingbirds have a unique form of flight that is somewhat insect like. The speed of a hummingbird's flight depends on the size of the bird. The average number of wing flaps is around 53 per second in normal flight. They are able to fly in all directions including forward, side to side, and even backwards. They are able to accomplish this through their highly modified and muscular bodies. Also they are able to control the angle between their body axis and the axis of wing rotation. They also have a very unique ability to hover. ("Frequently Asked Questions", Date Unknown)

We do not have information on home range for this species at this time.

Rufous-tailed hummingbirds have a distinctive call. It is a low pitched chup or chut sometimes done in a sputtering series. The notes sung include one or more shrill notes that rise and accelerate. The male hummingbird's song is whistled in a deliberate rhythm. For example: tse we ts we or tse tseu wip tsik tsew, followed by a pause. Males sing most during the early morning from dawn to sunrise. They sing on scattered perches near flowers or in small loosly assembled groups near flowers. (Stiles and Skutch, 1989)

The male hummingbirds use song to claim their territories. If another male attempts to enter, usually a loud chatter will be sung by the territory owner. Intruders such as larger hummingbirds, butterflies, and euglossine bees are sometimes attacked with a diving flight. (Gates and Gates, 2003)

Rufous-tailed hummingbirds feed on nectar and arthropods. Hummingbirds extract nectar from plants with their hollow, extensile tongues that are forked at the tip. They feed on a wide variety of plants including Antigonon, Callistrimon, Clitoria, Cosus, Isteria, Hamelia, Heliconia, Stachytarpheta, Tabebuia and Lantana. They also feed on a number cultivated tree species, especially banana and coffee trees. They feed on small insects and spiders by taking them from leaves and branches, a method called gleaning. They are very territorial when feeding, and intruders are attacked with diving flights. (Baker, 2003; del Hoyo, et al., 1999)

Due to their high metabolic rates, hummingbirds require a large amount of food in order to survive. They may need to eat several times their body weight in nectar in one day. ("Hummingbird", 2001; Baker, 2003)

The main cause of mortality for hummingbirds is predation of eggs and chicks in the nest. Predation on adult hummingbirds is uncommon. This is due to the agility hummingbirds possess in flight. Some known predators of hummingbird eggs, chicks and adults include: domestic cats (Felis silvestris), small hawks (family Accipitridae), small owls (order Strigiformes), shrikes (family Laniidae), roadrunners (genus Geococcyx), orioles (family Icteridae), western tanagers (Piranga ludoviciana), grackles (Quiscalus mexicanus), gulls (family Laridae), largemouth bass (Micropterus salmoides), frogs (order Anura) and mantids (family Mantidae). ("About Hummingbirds", Date Unknown; "Frequently Asked Questions", Date Unknown)

There has been co-evolution between hummingbirds and the flowers they feed upon. Hummingbird flowers have very distinct characteristics that serve to attract hummingbirds. They also have other characteristics to insure that pollination occurs. Many flowers are specially adapted to allow pollen to be deposited on hummingbirds in such a way that the pollen will reach another flower. This is a critical step in the process of plant reproduction. Hummingbird beaks are also specially adapted to feed from hummingbird flowers.

The specific plants that rufous-tailed hummingbirds obtain nectar from would not be able to survive without the birds to pollinate them. Some examples of plants pollinated by rufous-tailed hummingbirds include: Antigonon, Clitoria, Hamelia, Heliconia, Stachytarpheta and Tabebuia. (Grant and Grant, 1968)

Hummingbirds are important to humans because of their role in pollination. Rufous-tailed hummingbirds often pollinate important crops such as banana and coffee. Also, since these birds eat insects, they can play a very active role in pest control. They are also important in ecotourism and are popular amoung birdwatchers. (del Hoyo, et al., 1999; Grant and Grant, 1968)

There are no known adverse affects of rufous-tailed hummingbirds on humans.

Rufous-tailed hummingbirds are common or very common in most of their range. The birds have been able to adapt to man-made habitats and are therefore found around agricultural, suburban and urban areas. They are listed as Appendix II by CITES. (del Hoyo, et al., 1999)