Chestnut-sided Warbler

The Warblers with crisps, chestnut-sided plumage are not the ones who can be considered average among the many warblers. The Chestnut-sided Warbler comes with a yellow cap, a slender body, and a penchant for the thickets and second-growth forests. In spring, their plumage molts into gray as they head to coffee plantations and the forests of Central America. 

Today, we’ll learn about: 

  • Chestnut-sided Warbler color patterns, songs, and size
  • Chestnut-sided Warbler behavior, habitat, and diet
  • Chestnut-sided Warbler lifecycle, nesting, and migration range


Chestnut-sided Warblers Color Pattern

The name is an excellent indicator of what color pattern this particular species of Warbler possesses. Yes, as the name would suggest, there’s a generous patch of chestnut running down both sides of this warbler species. It starts right below their neck and extends over to their chest. Otherwise, breeding male Chestnut-sided Warbler has an overall white plumage for the base color. Then, the crown of their head is a lemon yellow. There is a black mask on their face, and their bill is also black in color. The cheeks remain a pretty shade of white. Their underparts are white as well. The wings are brown striped with some yellow at the upper parts. Their legs are black in color too. The upper parts also have patches of black over the white. 

Then, there are the breeding female Chestnut-sided Warblers. Smaller than the male warblers, they have the chestnut color dripping down their sides. The yellow crown takes on a faded, but darker shade of yellow. The bill and legs are black. The tail and wings are a mix of black, brown with shades of yellow visible on some parts. The overall plumage remains white along with white underparts. The streaks of black on their back are present but it is lesser in number. Instead of the deep, black mask on the face, there is a lighter black streak. 

Then, there are the non-breeding female and immature male warblers who share the same color patterns. The crown of these Warblers is yellow-green in color and they have white eyering around their eyes. The base color of their plumage is grey rather than white and this grey is present in the color of their cheeks. Unlike their name, the non-breeding ones actually don’t possess the chestnut streaks. If you saw them, there is a huge chance you won’t be able to recognize them with these color patterns alone because there are lots of Warblers with gray plumage. Their wings happen to be more black with the shades of the yellow present. The upper parts of their body have the same yellow-green color with some streaks of black. 

Description And Identification

The way to identify Chestnut-sided Warblers starts with first finding the right kind of habitat they live in. Thickets, second-growth forests, are some of the places Chestnut-sided Warblers love residing in. So, those are the areas they frequent the most. Then, let’s focus on the color patterns of Chestnut-sided Warblers. The name is indicative enough of the kind of color pattern this species of warbler has. In fact, the chestnut color running down the sides of their plumage is the biggest indicator that you are seeing a Chestnut-sided Warbler. 

Then, there is the yellow crown on their head. If it is a breeding male warbler, the yellow crown will be lemon yellow. If it is a female breeding warbler, the yellow crown on the head will be a deeper shade of yellow while looking dull at the same time. There are streaks of black on the back of both male and female Chestnut-sided Warblers. However, the streaks on the back of male warblers are deeper while those on female warblers are less obvious. They also have lemon yellow color decorating their wings, which is otherwise buff color. Then, there is the face. The face of the male warbler has a black mask while the mask present on the face of a female Warbler is far less deep. The plumage color of both breeding male and female warbler has white as the base. 

Nor, the immature and non-breeding ones are different. They are found in the tropics in winter and give no indication that they are Chestnut-sided Warblers. After all, the chestnut color is absent this season. Instead, they have a gray plumage accompanied by a yellow-green head crown. Usually, you won’t be able to specifically identify Chestnut-sided Warblers in this appearance and it is best you don’t make any attempt to do so. 

During nesting season, their songs are also a good indicator if you are in front of the right species of Warbler. While their songs sound similar to those of Yellow Warbler, a marked difference is the accented high note at the end. Overall, the sweet melody makes it sound like they are saying they are pleased to meet you with a definitive accent. This is the first song they sing and it is when they are defending their territory or trying to attract a mate. 

Then, there is the second song. They sing it when they are relaxed and deep into nesting season. This sounds exactly like that of a Yellow Warbler and there aren’t many human ears can do to differentiate. 

Chestnut-sided Warbler Song 

The male Chestnut-sided Warblers have two songs. There is a song they sing more often than the other. This one sounds like they are saying, “pleased, pleased, to meetcha”. Some assume they are saying they want to meet someone named Miss Beecher. It is a short song that ends with a high accent. Basically, you can hear an exclamation in the sentence when they finish. 

The second song they have is actually similar but the energetic ending is missing. As such, it sounds like a typical Yellow Warbler is singing the song. You can’t exactly pin it down to the work of a Chestnut-sided Warbler. The first song is sung by male Warblers to attract the attention of a potential companion. Later, once they are well into the nesting season, they switch over to the second song. Basically, it is a song they sing when they are relaxed. 

Their call is a rich, rather sweet one. Usually, you won’t be able to differentiate it from the call of a Yellow Warbler. 

Chestnut-sided Warbler Size

A Chestnut-sided Warbler has a long tail for its otherwise small body. They often lift their tail so that it rises above the line of their body, making it appear longer than it actually is. A Song Sparrow happens to be smaller than them but a Ruby-crowned Kinglet has every right to boast about being bigger than this species of warbler if they were inclined to do so. 

In length, they stop about 12 to 14 cm. In weight, they tend to be around 10.7 g to 14.3 g. Female Chestnut-sided Warblers are lighter than male warblers, due to the lack of excessive feathers. The wingspan is a generous 21 cm. Not too small for Warblers, not too big. 

Chestnut-sided Warbler Behavior

Chestnut-sided Warbler forages by hopping from one branch to another. They flitter among small trees and shrubs. They inspect the leaves and twigs to see if there are insects hiding there. They will hover around and then swoop in on their prey. Sometimes, flying insects are caught off guard as the bill of Chestnut-sided Warblers comes in contact with them and Swallows them. 

What Chestnut-sided Warblers Eat

Warblers and insects do not go together. That is pretty much their main source of food. When it is nesting season, they will eat moths, grasshoppers, flies, and caterpillars. Some berries also make their way into their diet. When they are wintering in the tropics, their diet tilts towards berries compared to before. Even so, about 90 percent of their diet still consists mostly of insects. 

Where Chestnut-sided Warblers Live And Habitat

Bushy pastures and slashings are some of the most beloved habitats of Chestnut-sided Warblers. They are good at expanding their habitat, slowly growing their range as they lost more and more forests in the east of the U.S. For breeding, they prefer fields with overgrown pastures, forest edges, young deciduous wood forests. Bushy thickets and briers are where they like residing in. Chestnut-sided Warblers choose to spend their winter in second-growth forests and forest edges. 

Range and Migration

These migratory birds spent their winters in the south of Central America and north of Colombia. There have been times where they have been sighted in south Ecuador but those instances are unconfirmed. In western Europe, they appear as vagrants. They go back to their breeding range when it is May. Then, by the middle of September, they are ready to take off again. Most of the migration takes place at night. 

Chestnut-sided Warbler Lifecycle

Chestnut-sided Warblers usually give birth to 4 eggs. Of course, sometimes they have 3 eggs in a brood instead of a fuller nest of 5. The eggs are usually white with splotches of brown on the edges. It takes them about 11 to 12 days to incubate the eggs. It is only the female Chestnut-sided Warblers who take part in the incubation process. Unfortunately, this species gets their nests invaded by cowbirds frequently, who lays their eggs on the nests slyly. 

The nestlings are fed by both sets of parents. About 10 to 12 days after the eggs have hatched, the young ones are considered old enough to leave the nest. 


The songs of Chestnut-sided Warblers play a big role in helping the male Warblers defend their territory. The courtship season sees male warblers grooming their feathers and their entire plumage, raising their crown feather and stretching their wings and tail while vibrating. 

The nesting site is in a shrub area that is low in denseness or has tangles. Blackberry is amongst their favorite sites. They also like Alder or maple, which are deciduous youngins. The nests are open cups once constructed in a loose manner by the female Chestnut-sided Warbler. Grass, rood, cedar, bark strips of grapevine, etc are used to build the nest. Animal hair and grass is used to line up the nest neatly. The twigs which have spiderwebs attached on them are often areas where they keep their nest. 

Anatomy of a Chestnut-sided Warbler

Chestnut-sided Warblers are small, fluffy birds. The male warblers especially have so many feathers that they look heavier than they actually are. Overall, they have a slender body with a slightly rounded stomach. Their head is extremely small. To the point, their eyes appear big for their head even though it is small too. They have a straight, proud bill and genuinely small legs. Their tails are often raised so that they appear bigger than their bodyline. Their wings remain close to their body but when they stretch it out, the wingspan is small but appropriate for the body of a warbler. 

Final Thoughts

Chestnut-sided Warbler tends to wander around edges of highways, clearings, or sites with deciduous trees of the young range growing in disturbed areas. Keep your ear open to hear their sweet songs, the ones where they sing about being happy about meeting you. Their songs have higher notes of emphasis than those of Yellow Warbler but the melody is more tightly knit than American Redstart. 

Be on the lookout for Chestnut-sided Warblers when they are foraging. They keep their tail lifted while their wings are lowered. They happen to stay on small trees and shrubs, right on the outer branches. They keep their foraging area lower compared to other warbler species. If they hear phishing sounds, they might approach to investigate the cause. 

One thing, as a birdwatcher, you don’t have to worry about Chestnut-sided Warblers disappearing from this planet any time soon. In fact, compared to the 19th century, they happen to be a far more common sight today. In the east, the species has an even bigger second-growth success. The recent decades have seen a drop in number but it is still stable. 


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Bird Watching Binoculars for Identifying Chestnut-sided Warblers

The most common types of bird-watching binoculars for viewing Chestnut-sided Warblers 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.

Chestnut-sided Warbler Stickers

Stickers are a great way for you to display your love for bird watching and the Chestnut-sided Warbler. Here is the sticker pack we sell with a Chestnut-sided Warbler sticker.

Bird Feeders For Chestnut-sided Warbler

There are many types of bird feeders. Bird feeders are a great addition to your backyard. Bird feeders will increase the chances of attracting birds drastically. Both kids and adults will have a great time watching birds eat at these bird feeders. There are a wide variety of bird feeders on the market and it is important to find the best fit for you and your backyard.

Best Bird Houses For Chestnut-sided Warbler

There are many types of birdhouses. Building a birdhouse is always fun but can be frustrating. These 4 birdhouses have become our favorites. Getting a birdhouse for kids to watch birds grow is always fun. We spent a little extra money on these birdhouses but they have been worth the higher price and look great.

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