What a Surprise!

Tonight I’m having one of those moments that remind me why I love birding so much: you just never know what you’ll find.

I’m pretty pumped right now, and didn’t plan on posting tonight, but wanted to share my excitement with you,  my BirdNation friends :-).

It was perfect timing. I opened up my e-mail on June 17 to read my daily New Jersey Rare Bird Alert from ebird. And I got excited, because there was finally a rare bird in my county, only 15 minutes away. Just in time for my summer break to start.

Here’s the thing about the NJ Rare Bird Alerts. Most of what comes up is not in my county. And I mean they are not even remotely close. Many of the people reporting these rare birds live in North Jersey (I’m a South Jersey girl), so unless I drive a minimum of 2 hours (which is not happening) I will not see these birds. But I opened that e-mail, which told me there were Dickcissels in Laurel Run Park, and got excited. “I can go there, it’s up the road from Boundary Creek!”, I thought. And I had all the time in the world because I was on vacation! So the rare bird search began.

Laurel Run is a meadow habitat that is a square trail one mile long. It meets up with Rancocas Creek. I had never been there before, but Dave and I have driven past it a few times, wondering if it was just a field. Over the next few days we visited the park twice, and walked the loop 3 times.

No Dickcissels.  “Oh well”, I thought, “at least we tried.” We did see some other good stuff. Mourning Doves, Red-winged Blackbirds, Barn Swallows, Yellow Warblers, an Indigo Bunting. We did figure out that we saw some Grasshopper Sparrows, which is a life bird for us.  We saw a few things we didn’t recognized, but got a few pictures.

So tonight I was looking through those pictures. And that’s when the excitement started.

The Indigo Bunting…was not. It’s a Blue Grosbeak! It’s bill is so thick! Another life bird.

Blue Grosbeak (Image by David Horowitz)

Then there’s Mystery Bird. I could not, for the life of me, figure out who this little guy was. Dave and I were thinking some sort of thrush maybe. I used all my field guides, and even my new Sibleys wasn’t being much of a help because I wasn’t sure where to look.

Mystery Bird…(Image by David Horowitz)

I resorted to Facebook. I posted my (not very good quality) photos on the New Jersey Birders group, and within 5 minutes got 3 responses: Juvenile Horned Lark. Other people in the group got excited about it too, and start sharing their pictures of the same Horned Lark.

Juvenile Horned Lark! (Image by David Horowitz)

And…that was not what I expected at all. But I’m so excited. I thought we didn’t see much at the moment we were there, but learned we did great! I didn’t see the Dickcissels, but I ended up with 3 new life birds and didn’t even know it at the time: Grasshopper Sparrow, Blue Grosbeak, and Juvenile Horned Lark.

And that’s one of the many (million) reasons I love birding. It’s better to go without expectations, because anything is possible. You just never know what kind of cool birds you might run into in the field 🙂

American Oystercatcher: Seashore Saturday

Hello friends! This week we are starting a new feature to celebrate the summer: Seashore Saturday! I was raised at the Jersey Shore, so the beach and ocean are very special to me. I don’t live at the shore anymore, but I look forward to taking birding trips at the shore every summer. Many people in New Jersey spend the weekends at the shore, so I figured I could give you a little glimpse of the shore each weekend (even if you don’t live near the ocean!). So this summer we will be exploring some of the shorebirds and seabirds you would find on the coasts if you spend time out on the ocean or on the beach.

Shorebirds and Seabirds are not one in the same. These are actually two distinct groups. Shorebirds are small to medium-sized birds that are found on the beaches and along the water’s edge. This group includes true sandpipers, avocets, oystercatchers, and plovers. Seabirds can be seen along the coastline but many are pelagic, meaning they spend most of their time on the open ocean. Seabirds include terns, gulls, auks, kittawakes, albatrosses, petrels, pelicans, and noddies, just to name a few. Throughout the summer I will be featuring birds from both groups.

Today’s shorebird is one of my personal favorites: the American Oystercatcher.

American Oystercatcher (Haematopus palliatus)

Description:

American Oystercatcher are large shorebirds that are about the size of a crow. They have black heads/upperparts, white underparts, and a bright, long red-orange bill. Their yellow eyes have a red ring around them and they have pale pink legs. Males and females look identical. American Oystercatchers can be found combing the beach for their main food source: bivalves (mussels, oysters,  and clams).

A pair of American Oystercatchers (Image by David Horowitz)

Range:

Atlantic Coast of the United States from New England down to Florida, Gulf Coast down to South America. Also found on the Pacific Coast of California, Mexico, and down to Chile

Habitat:

Always found near salt water habitats, beaches, mudflats, islands, sandbars

Food:

Shellfish, oysters, clams, mussels, marine worms, sand crabs, jellyfish, sea urchins. American Oystercatcher forage in shallow water and use their long bills to break open shells. They have two techniques for breaking shells: hammering the shell or finding a shell that is slightly open and jabbing its bill inside to clear the contents.

(Last summer Dave filmed an American Oystercatcher foraging at Barnegat Lighthouse State Park. Here’s the footage)

Breeding and Nesting:

American Oystercatchers start breeding when they are 3-4 years old. Sometimes they form pairs for life, but sometimes they may form trios of one male and two females to tend to a nest. Both males and female will create a nest on the ground by scraping out sound and lining it will pebbles or shells. Nests are usually found in sand dunes or  marsh islands above the high tide mark. They will make multiple nest sites, but only line one.Oystercatchers have one brood per year with a clutch size of 1-4 eggs. There may be 5 or 6 eggs if two females are sharing a nest with a male. The eggs are incubated for 24-28 days. The young will leave the nest within a day after hatching and be fed by the adults for about 2 months. The chicks will take their first flights at about 5 weeks old.

Sounds:

Loud wheep! whistles

American Oystercatcher (Image by BirdNation)

Fun Facts:

• Courting pairs will walk together making a loud single piping note. They will proceed to bend over, extend their necks, and run while calling side by side. Sometimes they will go into flight and be joined by other Oystercatchers in the area.
• Atlantic Coast and Pacific Coast Oystercatchers  are considered different races. The Pacific race is from Baja California southwards; north of Baja the species of Black Oystercatchers are prevalent.
• They can be confused with Willets during flight, because both birds flash black and white as they fly. However, the American Oystercatcher’s bright bill is noticeable during flight.

The Master Mimic

One thing I like about being off for summer is that I don’t have much of a routine. After having a strict schedule of teaching and taking classes for a majority of the year, it’s a very welcome break. There is one routine that I tend to pick up while I’m home each summer that I really enjoy: the Daily Mockingbird.

Around this time of year I see at least 2 Northern Mockingbirds a day. It doesn’t matter what the weather is or where I’m going; there’s always a Mockingbird somewhere. It used to be a random thing, but now I’m starting to notice some regulars in the same spots around the same time of day. It always makes me smile, because I’m a fan of of the Mimidae family of birds, which the Northern Mockingbird is a member of. So today, I wanted to share some fun facts about this fascinating bird.

Northern Mockingbird (Image via wikipedia.org)

1. Northern Mockingbirds like to be the center of attention.

Mockingbirds are pretty conspicuous. They like to make their presence known by finding the highest perch around to sing their songs. Although they like to be the center of attention, they do not appreciate intruders in their territory. They are very aggressive and not afraid to attack other birds, dogs, cats, and even humans who venture to close. They prefer to spend their time in large open fields and lawns, where they hop, walk, and run around to find insects.

2. Although they look pretty plain, they have some pretty impressive wing patches.

Northern Mockingbirds are a pale gray overall with white underparts. They have something pretty cool under their wings though: large white wing patches. These patches make Northern Mockingbirds pretty easy to identify while in flight. They will use the “wing flash” display  frequently, where they will open their wings either fully or halfway. We are not sure why exactly they do this. A theory is that they use their white patches to startle insects to make them easier to catch. They may also prance towards an intruder slowly flashing their white patches.

A Mockingbird uses the “wing flash” display (Image by Kelly Colgan Azar via ebirdr.com)

3. Northern Mockingbirds are masters at mimicking others and sing really impressive songs.

Mockingbirds are appropriately named. They are professionals at mimicking the sounds of other birds and frogs that live in the area. Their songs are made up of short phrases that may be repeated 2-6 times before they pause and start a new sound. Mockingbirds learn new songs throughout their lives and may learn up to 200 different songs. Both males and females sing. Males will sing from February to August, then again from September to November. They have different sets of songs for spring and autumn. Females usually sing in the autumn in a quieter voice. Their songs may get quite long and Mockingbirds will sing all throughout the the day into the evening.

4. They are not only good at singing animal sounds, though.

Although they mainly imitate other birds, Northern Mockingbirds also imitate unnatural sounds. Some examples include sirens, squeaky gates, and cameras. Another animal sound they are know for is imitating barking dogs.

Singing away… (image by Lillian Stokes via stokesbirdingblog.blogspot.com)

5. Unmated males are particularly determined singers.

Not only will they sing during the day, but unmated males are known to be nocturnal singers. They will sing throughout the night to be more attractive to potential mates. They tend to sing nocturnally during the  full moon. Nocturnal singers can sing up to 1,000 songs per hour!

6. Northern Mockingbirds used to be pretty popular pets.

From the late 1700s to the early 1900s, people would cage Mockingbirds as pets. People were attracted to their beautiful songs. They were so popular that they almost disappeared in the wild in some parts of the East Coast. Some particularly impressive singers would sell for around $50! Thankfully, they are no longer pets and have become widespread again. In recent years they have expanded their range northward.

On the Cornell Lab of Ornithology’s website, the first paragraph about Northern Mockingbirds states: “These slender-bodied gray birds apparently pour all their color into their personalities.” I couldn’t agree more. Northern Mockingbirds have really interesting personalities, and I think it’s safe to say they deserve the title of “Master Mimic.”

Do you have a Northern Mockingbird that lives nearby? Tell me about your Mockingbird experiences in the comment section.

A Rare Summer Solstice

Happy Summer Solstice everyone! It’s the longest day of the year in the northern hemisphere. I can’t believe summer is already here; seems like spring just began yesterday. This year’s solstice is extra special: it coincides with the Strawberry Moon. The Strawberry Moon is a name given by the Algonquin tribes to the full first full moon of the summertime. They knew that fruits, such as strawberries, were ripe for picking during the Strawberry Moon. Today is a rare event: the full moon and summer solstice only occur on the same date around every 70 years. The next time the strawberry Moon is to happen on the summer solstice is June 21, 2062. Pretty cool, right?

I’m happy to say that I am on summer break since my school year ended last week. I plan on focusing more my bird studies now that I have time off (of course relaxing too!). This summer will be the summer of shorebirds: the new summer feature will begin on this blog sometime this weekend. I also hope to add more informational posts on bird behavior over the next few months.  I’m excited for things to come!

This afternoon Dave and I visited Haddon Lake Park. I honestly didn’t expect to see to much. Here’s why: when its hot, especially mid-day, birds want to stay cool just like we do. So it’s harder to go birding in the summer because everyone is hiding away to try to beat the heat.

I was pleasantly surprised though. It was pretty busy at the lake, with a variety of species. My favorite part was a pretty unique family of ducks.

There are a lot of waterfowl who live at the lake. They are mainly Mallards and Canada Geese, but there are some domestic species too. We were looking at some resting Mallards when all of a sudden two large brown ducks came waddling quickly out of the water. They didn’t look like female Mallards because they were too big. Then three more ducks appeared; another brown, one all white, and the other black and white.

They were the oddest group of ducks I’ve ever seen. The original brown ducks were about the size of the all white one, but have blue speculum patches on their sides like a Mallard. The black and white one looked like it came straight off a farm. I think we were seeing hybrids of a mix between one of those white domestic ducks and a mallard. They certainly had features of both. You never quite know with ducks because they hybridize all the time.

They stood around for about a minute then got in a line to continue on their mission, whatever that was. Then the five of them formed a little pod and scurried across the grass. As they waddled away I couldn’t help but giggle at them. Their little family was just so adorable. They certainly made my day :-).

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Fun at Forsythe NWR

On Sunday Dave and I visited Edwin B. Forsythe NWR. I make it a point to visit Forsythe at least once a season. I always see something interesting no matter what time of the year I visit, so I was looking forward to seeing what we would discover.

We usually hike a little bit of the Songbird Trail, but it was already getting hot so we went straight for the 8 mile Wildlife Drive. At the beginning of the drive there’s an observation platform that goes out into the marsh. There’s an Osprey nest there, so we like to check out the family in the summer. A few visits ago we observed a small flock of Glossy Ibis foraging there, so I was hoping to see Ibis again.

There were no Ibis but we did see a family of Ospreys (3 chicks on the nest), Barn Swallows, Red-winged Blackbirds, and a Yellow Warbler. Down below were hundreds of Fiddler Crabs! They were trying to get away though, because a turtle came parading through the mud. The little guy moved pretty quickly like he was on a mission. Although the Fiddler Crabs were scurrying away, he seemed to have no interest in them. He had places to go I guess. Then we heard a call.

‘Ttp Zhe Eeeeeee!”

The call came from within the tall grasses. I’ve heard this call before, but  wasn’t sure who it was. As we scanned the marsh, suddenly a little brown bird popped up from the grass.  Ttp Zhe Eeeeeee!

There it was! A Seaside Sparrow. Seaside Sparrows are drab, with a yellow spot over their eyes, and a large bill. They are usually heard and not seen, so I was shock when it popped out of nowhere. It was our first life bird of the day.

Seaside Sparrow (Image by David Horowitz)

Turtle on the go! (Image by David Horowitz)

The tide was low, so the first part of our journey was all mudflats. As we continued there was more water, so that’s where all the action began. It was busy: a family of Mallards, Glossy Ibis (finally!), Great Blue Herons, Canada Gee, Laughing Gulls, and Double-crested Cormorants. As I was taking notes Dave asked, “Hey, are those birds over the the skimmer things you were talking about?”

Glossy Ibis (Image by David Horowitz)

Black Skimmers! A dream bird of mine. Every time I visit Long Beach Island during the summer I hope to see Black Skimmers, but never do. There were about 4 of them skimming along the water. Black Skimmers are unique because their lower mandibles are much longer than their upper one. They keep their bills open as they skim the water’s surface until they hit a fish. I was happy seeing them, but wasn’t prepared for what would happen next.

Black Skimmer (Image by David Horowitz)

On the other side of the marsh something big was happening. There was a flurry of black and white in the distance. I thought it was a bunch of gulls and terns, but it was more exciting than that. It was a huge flock of Black Skimmers coming our way!

I’ve never experienced something quite like it. There had to be at least 200 of them.They were everywhere! And they were loud too, all calling out “Yip! Yip!’. The flock split; some went out towards the ocean, while the rest did a loop around the marsh before landing together in a mudflat. It was by far one of the most thrilling displays I experienced at Forsythe.

A group of Black Skimmers (Image by David Horowitz0

We continued on and saw another one of my favorite birds, Snowy Egrets. They were stalking around looking for fish while Herring Gulls and Common Terns flew and dove overhead. There were also Great Egrets, Grackles, Red-winged Blackbird, Willets, Lesser Yellowlegs, Tree Swallows, Crows,more Osprey families, and a family of Mute Swans with 2 cygnets.

Willet (Image by David Horowitz)

Common Tern (Image by David Horowitz)

Mute Swans (Image by David Horowitz)

Toward the end of the trail there were some terns hanging around. I’ll admit, terns are new identification territory for me. I was able to figure out that I was seeing some Common Terns, but there was another kind as well. They had black heads, all black bills, and black legs. Turns out they were Gull-billed Terns. They are usually uncommon, but a birder from a Facebook group I’m in told me that they have been starting to breed at Forsythe. It was our final life bird of the day.

Gull-billed Tern (Image by David Horowitz)

I learned later in the day that Dave and I saw a something rare during our trip. There were 3 Ruddy Ducks hanging out not far from the Gull-billed Terns. I was a little surprised to see them, but we took a few pictures and moved on. In the evening I received my daily E-bird NJ Rare Bird Alert E-mail and the 3 Ruddy Ducks were on there. They should have left for the season, but for some reason these ones stuck around. This was the first time I saw one of the birds on the Rare Bird List in person. I submitted my checklist that night and the following day my Ruddy Duck report and comments were on the e-mail. I know that’s such a bird nerd thing, but I was excited about it! 😛

As usual, Forsythe NWR never fails to please. If you’re ever at the Jersey Shore and want to go birding you should definitely spend a day at Forsythe. Have you done any shore birding lately? If you have, what kind of shorebirds are you seeing?

Ruby-throated Hummingbird: Migration Monday

Hello! Today is the finally Migration Monday of the spring season. Can you believe that summer begins in one week? Next week I will start a new weekly feature about Summer Shorebirds (not sure which day of the week yet). The migrant I picked for today is a great lead-in to summer: the Ruby-throated Hummingbird. I plan to write more about hummingbirds in the upcoming months, but I specifically chose Ruby-throated today because it is the only hummingbird I get in my area.

Ruby-throated Hummingbird (Archilochus colubris)

Description:

Ruby-throated Hummingibrds are aptly named; males have a brilliant patch of ruby feathers on their throats that glisten in the sun. These tiny hummingbirds, who are about 3.75 inches tall, rapidly buzz from one nectar source to another. Rubies have emerald green bodies and slightly down-turned bills. While sitting, their wings do not reach all the way to their tail. The red throat of the males may seem dark when they are not in good lighting. Rubies are precision flyers that can stop instantly and hover while adjusting their bodies with amazing control. They are common summer visitors to flower gardens and nectar feeders.

A  beautiful male Ruby-throated Hummingbird (Image by Paula Cannon/VIREO via audubon.org)

Range:

Medium to long-distance migrants. Winter: Central America and the southern part of Florida. Migration: Mexico, Texas, and the Great Plains region of North America. Breeding: Eastern North America and parts of Canada. Ruby-throated Hummingbirds are the only Eastern hummingbird. Some migrate across the Gulf of Mexico to their wintering grounds in a single flight. Many will migrate along the coast of Texas. In the spring, males migrate north earlier than the females.

Habitat:

Deciduous wooded areas or the edge of woods, orchards, meadows. They prefer to be near flowers for their food source, so they are common in gardens and backyards. They spend time in open or dry tropical scrub while at their wintering grounds in Central America.

Food:

Nectar from orange and red tubular flowers such as honeysuckle, jewelweed, red morning glory, and trumpet creepers. They will also eat insects from spider webs or grab them from mid-air. Rubies will put their bills into flowers and extend their long tongues to eat nectar while hovering.

Male Ruby-throated using his tongue at a flower (Image via aspensongwildbirdfood.com)

Breeding/Nesting:

To attract a female, males will make looping,  U-shaped dives from as high as 50 feet above a female while making a whirring sound. The female will construct a nest in either a shrub or tree on a horizontal branch 10-40 feet above the ground. Females will use grass, spiderwebs, and plant down to construct a nest that is the size of a large thimble. Rubies can have 1-3 broods with a clutch size of typically 2 eggs. Females incubate the eggs for 11-16 days and the young will fledge after 20-22 days. The nest stretches as the young grow.

A female feeds her young (Image by Scott Bechtel, National Georgraphic You Shot)

Sounds:

In flight, the male’s wings create a faint high buzz. At daybreak males will make a series or monotonous chips. During the courtship dive displays, males will make a high rattling t-t-t-t.

Fun Facts:

• Ruby-throated males will aggressively defend flowers, and may get in fights and chases over them.
• Although they are the only hummingbird in the East, Rubies occupy the largest breeding ground of all North American hummingbirds.
• Ruby-throated Hummingbirds can beat their wings about 53 times per second.
• They have extremely good color vision and can see on the ultraviolet spectrum.

I have a favorite Ruby-throated moment: last summer I went river tubing at a campground. While waiting for the shuttle I discovered 6 hummingbird feeders behind the office building. There were at least 40 Ruby-throated Hummingbirds buzzing all over! I was bummed though because my phone was in the car so I couldn’t take a picture (wasn’t bringing my phone on the river!). I will never forget that moment though.  It was an amazing sight! Do you get Ruby-throated Hummingbirds in your area? Do they visit your feeder or garden? Tell me about it in the comments!

Nest Watch!

Hello friends! I wanted to post today to catch up on the past month or so. The end of the school year is approaching (I’m a teacher), so things have been pretty hectic and I haven’t posted much. Even though its been busy I have been birding, so here are some of the highlights from the past weeks.

I feel so lucky to have been able to do some nest watching this spring. I found two Yellow Warbler nests at Boundary Creek. One of the nests we found was just being started by a female at the time. A few days later we were able to see the results of her hard work. It’s amazing how quickly birds will build these amazing nests. Here’s the before and after.

Beginnings of a Yellow Warbler nest (Image by BirdNation)

Yellow Warbler’s finished product (Image by BirdNation)

Last year at Boundary Creek we discovered a Barn Swallow nest on top of a light near the bathrooms. We ended up observing the nest throughout the season. This particular female had two broods with about 3 chicks fledging per brood. A few weeks ago we checked the nest and there she was! I haven’t seen chicks yet, but she was sitting on the nest. I was wondering about her so I’m glad to see her again.

Barn Swallow on her nest (Image by BirdNation)

In mid-May Dave and I spotted a female Baltimore Oriole hanging around a sycamore tree at Strawbridge Lake. It turns out she was constructing a nest. Baltimore Oriole nests are really cool because they make hanging sacs. The female will lay her nesting material on a branch and by randomly poking starts to form knots. It takes about a week for a female to finish a nest. (If you want to learn more about Baltimore Orioles and their nests, check out my Migration Monday article about them here)  A week later I found her beautiful completed nest.

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A few months ago House Sparrows moved into our nest box. We weren’t seeing much happening on our nest box cam for awhile except the shuffling of sticks. About a week ago Dave turned on the cam and there was a chick! It was waiting to be fed by its mom. House Sparrows make messy nests, so we didn’t realize there were eggs. I’m not sure how many chicks there were, but there were at least 2. They fledged a few days ago.

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Have you observed any nests this spring? Tell me about it in the comments. I would love to hear about them!

Ovenbird: Migration Monday

Hello friends! It’s almost summer, so we will be wrapping up Migration Monday next week and starting a new summer feature. Today we will feature the Ovenbird.

Ovenbird (Seiurus aurocapilla)

Description:

Ovenbirds are larger members of the Wood Warbler family. They are chunky songbirds who usually points their tails straight up. Ovenbirds have olive-green upperparts and dark streaking on their white underparts. They have a white eyering, rufous/black crown streaking on their heads, and pink legs. Ovenbirds are unusual from other wood warblers because they spend most of their times on the ground strutting deliberately with their short tails pointed up.

Ovenbird (Image by Cephas via wikipedia)

Range:

Long distant migrant. Summer (breeding): Eastern United State and Canada. Winter: Mexico, the Caribbean, Central America, northern Venezuela, and Florida. Migration: Southeastern and Midwestern United States

Habitat:

Ovenbirds spend most of their time near the ground, making them hard to spot in the field. They breed in mixed or deciduous forests. In the winter they live in the tropics in habitats ranging from dry highlands to wet forests in lowlands.

Image by Greg Lavaty via houstonaududon.org

Food:

Ovenbirds forage through the leaf litter looking for insects and other invertebrates. In the winter they will add seeds to their diets. Sometimes they will forage higher in the trees or in mid-air.

An illustration of an Ovenbird Nest (Image via the Cornell Lab of Ornithology)

Breeding/Nesting:

Males sing to attract females to their territories. The males defend their territories by dropping their wings, pointing up their tails, and stomping the ground with their feet. Female Ovenbirds build their nest on the ground in a dome shape with a side entrance. They were named “Ovenbirds” because their nests resemble dutch ovens.

Ovenbirds will lay 4-5 and have 1-2 broods per year. Sometimes Cowbirds paratisitze Ovenbird nests, but the chicks usually survive even with the cowbird intruders. The female incubates the eggs for 11-14 days and the chicks fledge 7-10 days after hatching. When the chicks fledge they can only flutter and hop, so the parents will continue to them for 10-20 days. Some years Ovenbirds can have up to 3 broods depending on spruce budworm outbreaks.

Songs and Calls:

A rapid and staccato “teacher” song. tea-cher, tea-CHER, TEA-cher! that gets louder over the first few repetitions.

Fun Facts:

• Ovenbirds mainly migrate at night.
• They are one of the few birds that will sing throughout the heat of mid-summer afternoons.
• Males who live near each other will often sing together. One male will start singing immediately after the other finishes, making it sound like only on male is singing. They may alternate up to 40 songs.
• Once Ovenbird chicks start to leave the nest, the parents will split the brood in order to care for them. The male keep his chicks in the territory while the female brings her chicks to an adjacent area. The chicks don’t fledge until they are around day 30 and will stay on the breeding territory after their parents leave for the wintering grounds.

The Tricksters

It was a beautiful spring afternoon at Amico Island. I was on a quest to find warblers, and I was excited when I spotted a life bird in the meadow.

It was a male Common Yellowthroat. There was also another bird with it. Common Yellowthroats are tiny warblers that are yellow and olive with a black mask over the eyes. The other bird though…was strange. It was almost double the size and brown. The big bird was crying for food while the little Yellowthroat tirelessly tried to satisfy it with whatever food it could find. Then it hit me: the Common Yellowthroat was feeding a Brown-headed Cowbird chick! Brown-headed Cowbirds are brood parasites. This male Yellowthroat had no idea that he was feeding a chick that was not even the same species as him. How did this happen?

A juvenile Brown-headed Cowbird with its Common Yellowthroat parent (Image by Darin Ziegler via allaboutbirds.org)

There are about 100 species of birds that are considered brood parasites. Parasitic birds don’t want the responsibility of raising chicks; they pass that on to other unsuspecting bird species. These birds are sneaky: they will target females of other species and lay their eggs in that nest instead of creating one of their own. Why would they do this? Parenting consumes a large amount of time, resources, and energy that can be saved by having another bird do all the work. So then how do brood parasites pull off such trickery?

Brood parasites may  use different technique in order to invade a nest. Sometimes a bird will patiently wait for the host to leave the nest so they can sneak in. Certain species will use a “disguise” by mimicking other harmless species to fool the host.. For example, in this study found in Proceedings of the Royal Society B, biologists learned that Cuckoo Finches  from Africa will attempt to fool Tawny-flanked Prinias by pretending to be the harmless Southern Red Bishops (Check out the studies by Claire Spottiswoode and other scientists here). Other will pretend to look like predators and scare the poor hosts right off the nest.

A Cuckoo Finch chick (left) and Tawny-flanked Prinias chick (right) (Image by Claire Spottiswoode

If a brood parasite successfully makes it to a host nest without being detected, it will lay eggs that look similar in size and color to the correct specie’s eggs. The parasite’s eggs will be thicker but usually have a shorter hatch time than the host species so that the parasite will hatch first. Many birds cannot tell the difference between their eggs and the intruder eggs and raise whatever is in their nest. If the parasitic chick does end up hatching it will usually murder its siblings so it can get all the food. For example, Common Cuckoos have been known to push their sibling’s eggs right out of the nest to avoid them from ever hatching. African Honeyguide chicks will stab their siblings to death with their sharp hooked bills.

All of this sounds pretty terrible, right? However, it’s not always victory for the brood parasite. Many host birds are discovering these tricks and fighting back.  Some host species will lay eggs that have a unique pattern, or “signature” so if they see an egg that doesn’t match they will dispose or destroy it. For example, Gray Catbirds will puncture any parasitic eggs they discover. Superb Fairy-wrens from Australia will teach their chicks a specific sound while they are still in the egg. Only Fairy Wrens are able to learn it, so if the chick is not including the “password” while calling for food, the host will know who the intruder is. Other species form adult lookout groups to catch and attack brood parasites while certain species will design their nest so that the invader gets trapped.

Superb Fairy-wrens (Image via australianbushbbirds.info)

Brood parasites and their hosts are a fascinating example of avian evolution. While parasitic birds like the Brown-headed Cowbirds and Cuckoos are continuing to try and trick other species, the hosts are developing new strategies to defend themselves and their broods.

Have you ever experienced a brood parasite at work? Let us know if you have in the comments.