Curve-billed Thrasher

Curve-billed Thrashers are truly an interesting species to study. As their name suggests, they have characteristically decurved bills. Interestingly, their bills are not the most curved out of all the members of the Thrasher family. W.n Swainson, the naturalist who first published information about the species, coined their name before the existence of other Thrashers with curved bills were popularly known.

About Curve-billed Thrashers

You can spot these birds in the southern United States and parts of Mexico. They are mostly resident birds, but they do make minor seasonal movements. There are several recorded subspecies of Curve-billed Thrashers that vary slightly in appearance but have similar origins.

Another interesting caveat of these birds is their mimicry! They belong to the mimid family, and frequently mimic a wide range of other birds. This may confuse an amateur bird enthusiast, but do not worry! There is no shortage of unique identification factors that you will learn through this blog.

Now that we have piqued your interest, let us not waste any more time! In this article, you will learn about the following features:

● Curve-billed Thrasher Photos, Color Pattern, Song
● Curve-billed Thrasher Size, Eating behavior, Habitat
● Curve-billed Thrasher Range and Migration, Nesting

GET KIDS BIRD WATCHING

Curve-billed Thrasher Color Pattern

The color of their overall plumage is grayish brown. They have white throats, and their underparts fade into a lighter, ruffled gray that appears speckled with deeper gray feathers or beige skin on the abdomen. Their wings have whitish-gray wing bars, especially in the eastern populations. Their tails are a pale hue.

They have bright yellow-orange or red irises, with orange rings outlining them. They have blackish-brown bills and blackish-brown legs. The basal portions of their lower mandibles are usually paler.

There are also records of adult Curve-billed Thrashers that are almost completely albino.

Juveniles follow a similar color pattern but are less spotted. The inside of their mouths are bright ochre, and their tongues have black spots.

Description and Identification

These birds are medium-large pale brown thrashers with smooth brown upperparts and circular specks on their paler underparts. There may be visible beige skin on their underparts. Their bills are elongated and decurved. However, they do not have bills with the most curvature out of all the Thrashers. They were discovered before the recordings of Thrashers with curvier bills, so this may not be the most accurate field mark.

Adult males and females have similar appearances. Juveniles have shorter and relatively straighter bills.

There are minor visual variations across subspecies. The oberholseri subspecies, which you can find in southeastern Arizona and throughout Texas. They have clearer spots on their underparts and vivid wing bars, and bigger tips on their wings. The palmeri subspecies, found in the West, have less distinct spotting and shorter tips on the tail.

Curve-billed Thrashers are similar in size to the American Robin, but the former are slimmer with longer tails, and grayish brown. American Robins, on the other hand, have longer, more slender bodies, with lighter feet.

Although similar in appearance, Curve-billed Thrashers are vocally divergent from other species of Toxostoma thrashers. Curve-billed Thrashers have a distinct “whit-wheet” sound and have minor visual cues that differentiate these other birds that overlap within their range.

You can find both the LeConte’s Thrasher and the Curve-billed Thrasher in central and western Arizona as well as northwest Sonora. The latter have darker breasts, heads, backs, and tails.

Bendire’s Thrashers also overlap in range with the Curve-billed seasonally in Arizona, western New Mexico, and northern Sonora. The former has shorter, less decurved bills, and are grayer overall with the base of their lower mandibles a pale fleshy yellow color. The nestlings of the two species appear almost identical, but Curve-billed Thrasher nestlings have black spots on their tongues, lacking in the nestlings of Bendire’s Thrashers.

Crissal Thrashers can be confused for this species in Arizona, New Mexico, and northern parts of Mexico. However, Curve-billed Thrashers have spotted, darker breasts than Crissals, who also have dark, rusty under tail coverts. Crissal Thrashers have more curvature in their bills than Curve-billed Thrashers. The Long-billed Thrasher permanently resides in southern Texas and eastern parts of Mexico, it is commonly confused with the Curve-billed Thrasher. You can tell them apart by their tails, the Long-billed has a rufous-brown tail, while the Curve-billed has a gray-brown tail and prominent spots on their breasts.

Curve-billed Thrashers also have grayish-brown upperparts as compared to Brown Thrashers, who have rufous-brown upperparts. Brown Thrashers also have prominently streaked breasts and shorter bills.

Finally, Ocellated Thrashers can be mistaken for Curve-billed Thrashers in the highlands of central Mexico. However, they have a distinguishing abundance of circular black spots on their breasts and sides, which the Curve-billed Thrashers lack.

Curve-billed Thrasher Song

These Thrashers have a distinct “whit-whit” sound. After hatching, hatchlings make a soft, inconspicuous “whit-whit” sound from the 3rd day after they have hatched. Their first chirp notes are let out on their 16th day, and they develop adult song abilities by the 18th or 19th day. When they fledge the nest, they make loud calls from perches and other elevated surfaces.

Although their most commonly heard sound is the double whistle or “whit-whit”, they have a range of other vocalizations. They make deep, guttural notes, such as the scolding “churr”, which is lower-pitched in adult females. They also have Wren-like chatter, chirping (chirp-chirp), and a throaty “kuk” call. Further research is required to determine the motivation behind these different sounds.

Juveniles make check or chack sounds to beg for food, especially as fledglings. These birds are mimids and are capable of mimicking several other species, such as the Scissor-tailed Flycatcher, Northern Cardinal, Pyrrhuloxia, and occasionally the Black-headed Grosbeak.

Curve-billed Thrasher Size

The average range of length of adult Curve-billed Thrashers is 10.6 to 11 inches, and they can weigh anywhere between 2.1 to 3.3 ounces. Their average wingspan is 13.4 to 13.6 inches.

Curve-billed Thrasher Behavior

Curve-billed Thrashers behave shyly and are volatile but allow humans to examine them closely. They can be extremely aggressive while fighting away potential threats, over food or their babies.

Being members of the mimid family, they often mimic other species for protection or other purposes. However, they do not indulge in mimicry as often as other mimids. The extensive list of melodies they memorize earns them the title of cuitlacoche or songbird in Mexico.

They have a fast-paced walk while foraging. They switch between running with agility and hopping lightly, so as to not make their whereabouts obvious. On the 19th day after their hatching, they develop hopping abilities. They also climb trees vertically. Their flight consists of jerky, short, quick bouts, during which they spread their tails downward. They fly from one bush to another or near the ground.

Their preening methods are similar to other Thrashers. They begin by rubbing the tips of their bills over their breasts, backs, and then over their lesser wing coverts and shoulders. Following this, they move on to preening their faces using their toenails.

Preening begins the 13th day after they are hatched, but head-scratching begins only on the 22nd day.

A brooding female preens before dusk. Males have a longer preening ritual, taking up to 10 minutes at a time.

They roost in cacti, commonly cholla cacti, especially in Arizona. They choose horizontal branches near the main trunks. In the winter, they may choose to build platforms made of sticks on which they roost.

They sleep with their bills overturned over their backs. During the non-breeding season, one adult of the pair may sleep in the empty nest left by their fledglings.

These Thrashers are highly defensive. Their aerial displays include both birds rising vertically up to a height of 3.3 feet, fluttering their wings, and pecking at each other agitatedly. Following this, they fall to the ground and fight each other with their beaks and feet. The loser retreats with their bill open.

They also fight and chase each other near the nest, with chases lasting up to 15 minutes. Adult males sometimes attack their fledglings after they ward off intruders.

Juveniles fight each other by pressing their breasts together, keeping their wings slightly open, and peck at each other. They may hop into the air periodically. These birds mate for life, and the pair bonds last for as long as both members are present. If a member of a pair disappears or dies, the other adult finds another mate immediately.

They also have courtship displays. This includes following the Thrasher that they wish to mate with and singing a courtship song. They feign arguments. From courtship to nest-building, they take less than a month.

Curve-billed Thrasher Diet

Their diet consists primarily of insects, berries, and other small fruit. They also enjoy insect larvae. Insects commonly eaten by Curve-billed Thrashers include beetles, ants, grasshoppers, wasps, arthropods like spiders, centipedes, snails, and sowbugs. They also enjoy the fruits of the desert such as prickly pear and saguaro and can digest the seeds of cactus.

These birds forage mostly on the ground, using their thick, decurved bills to dig and drag into the soil. They also use their bills to turn over leaf litter, pebbles, and other obstructing materials. When digging into the unforgiving ground, they brace their tails against the soil and make swift, heavy downwards motions with their bills to make indents.

Curve-billed Thrashers Habitat

These birds are commonly found in southern America and parts of Mexico. They gravitate towards deserts and arid climates but avoid extreme desert regions with no cacti. Curve-billed Thrashers can also be spotted in suburban areas, where their beloved cholla cactus is in abundance. They also inhabit open grasslands and chaparral.

Range and Migration

These birds are largely non-migratory, but they do make some seasonal movements. The T. c. curvirostre subspecies, most commonly found in Mexico go to places of higher elevation to avoid overwhelming heat. As there is a large degree of dispersion and little research on the matter, it is difficult to determine more about their seasonal movements.

Curve-billed Thrasher Lifecycle

Incubation is done by both parents, and both develop incubation patches. The hatching process can take up to a full day, and siblings hatch within a day of each other.

Nestlings beg their parents for food with full-body motions, and both parents feed them. If the nest is in a particularly sunny area, the female shades her nestlings. The young leave the nest around 22 days after hatching. One pair produces an average of 2 and a maximum of 3 broods a year. The average lifespan of Curve-billed Thrashers is ten years.

Nesting

Pairs remain together year-round in their residential areas. The nests are commonly placed in the fork dip of the cholla cactus, 3-5 feet above the ground. Other plants include yucca, prickly pear, and thorny shrub.

The nest itself is a bulky, loosely packed cup structure of thorny twigs. They are lined with soft grass, rootlets, feathers, and animal hair. They may reuse these nests, or even build on top of nests made by other birds such as the Cactus Wren. Each clutch consists of 2 to 4 eggs, an average of 3. The eggs are a pale blue-green with tiny brown marks.

Anatomy of a Curve-billed Thrasher

These birds are medium-sized Thrashers, mimids of the desert. As their name suggests, they have decurved bills. Adult males and females have similar anatomies. They are heavy-footed. Juveniles have shorter and relatively straighter bills.

Final Thoughts

In conclusion, these birds are incredibly fascinating indeed. For us to understand this wonderful creature better, we must further study their subspecies. This will help us identify the potential behavioral difference and their causes.

Although these birds are common in their territories, their habits have suffered a blow at the hands of urban development. Agriculture in Southern Arizona has also encroached on their territory. While these are not a conservation priority, it would be interesting to create the conditions of their chosen habitats artificially.

Ornithology

Bird Watching Academy & Camp Subscription Boxes

At Bird Watching Academy & Camp we help kids, youth, and adults get excited and involved in bird watching. We have several monthly subscription boxes that you can subscribe to. Our monthly subscription boxes help kids, youth, and adults learn about birds, bird watching, and bird conservation.

Bird Watching Binoculars for Identifying Curve-billed Thrashers

The most common types of bird watching binoculars for viewing Curve-billed Thrashers are 8×21 binoculars and 10×42 binoculars. Bird Watching Academy & Camp sells really nice 8×21 binoculars and 10×42 binoculars. You can view and purchase them here.

Curve-billed Thrasher Stickers

Stickers are a great way for you to display your love for bird watching and the Curve-billed Thrasher. We sell a monthly subscription sticker pack. The sticker packs have 12 bird stickers. These sticker packs will help your kids learn new birds every month.

Bird Feeders For Curve-billed Thrashers

There are many types of bird feeders. Here are our favorite bird feeders for your backyard. We use all of these bird feeders currently. Kids will have a great time watching birds eat at these bird feeders. Using this collection of bird feeders will provide a wide variety and many types of birds.

Best Bird Houses For Curve-billed Thrashers

There are many types of bird houses. Building a bird house is always fun but can be frustrating. Getting a bird house for kids to watch birds grow is always fun. If you spend a little extra money on bird houses, it will be well worth every penny and they’ll look great.