Key Traits
What are the telltale features of the true finches—all the birds in the family Fringillidae? For casual observers, like most of us bird lovers and naturalists, this isn’t an easy question to answer.
We normally use a bird’s size and shape as the starting point for identification. The bird families I’ve covered in previous blogs have been easier to define by size and shape. Hummingbirds, pelicans, woodpeckers, and kingfishers all have distinct silhouettes.
But with most finches, it can be a challenge to distinguish them from other small songbirds by silhouette alone. The sizes and shapes of finches are often very similar to those of songbirds in other families. Like sparrows, for example. This is one reason that a bunch of distantly related birds have the word ‘finch’ in their common name. These so-called finches are actually members of either the New World Sparrow family, the waxbill family, the indigobird family, or the tanager family.
I’ve griped about common names before on other blogs. There are so many examples where two or more bird species have common names that imply a close relationship, even though they actually belong to different families. This can be confusing, especially when you’re new to the world of birding or ornithology.
One example is the world-famous Darwin’s Finches on the Galapagos Islands. There’s a Pulitzer prize-winning book about them, titled The Beak of the Finch. But are Darwin’s Finches true finches in the family Fringillidae? No, they’re actually in the family Thraupidae, which is filled with the many colorful tanagers of Latin America.
But we can’t really blame people for naming birds this way. They were just looking at the overall, superficial appearances of the birds. Back in the day, no one had genetic data to sort out which birds are related to which.
The Plum-headed Finch of northeastern Australia belongs to the waxbill family, Estrildidae. In other words, not Fringillidae. The well-known Zebra Finch is also an Australian bird in the waxbill family. So the Zebra Finch is not a “true finch.” This is all a long way of saying that common names can be misleading. They don’t always reflect the real genetic, evolutionary relationships among birds. This is certainly true for the many birds we commonly call finches.
So it sometimes takes a little extra effort on our part to figure out which family a bird really belongs to. These days, any respectable bird field guide or mobile app will present species taxonomically. Species will be grouped into their respective genera. Genera are grouped into families. And families are grouped into orders. So that’s pretty helpful. I recommend spending a little time with your book or app to see which fringillid finch species you have in your neck of the woods.
Okay, we’ve acknowledged that it’s not super easy to instantly recognize a true finch from a mile away, the way you can with, say, a heron or a penguin or a roadrunner. But that’s okay, and this is going to be the case for many types of songbirds. I mean, where would be the fun if every bird was easy to identify?
Let’s move along and talk about the features of true finches. As for size and shape, these are small to medium-sized birds. Among the smallest finches are the Lesser Goldfinch, the Andean Siskin, and the various Euphonia species. These finches are only about 4 inches, or 10 centimeters, long.
The largest member of the family might be the Collared Grosbeak, which lives in the Himalayas. This beast of a finch is about 9 inches long, or 23 centimeters.
Finches have compact bodies with relatively large-ish heads supported by short necks. Many of them have tails with notched or forked tips.
Plumage colors vary a lot among finch species. Some are rather drab, with streaky brown or gray feathers. These guys fall into the category that birders call “Little Brown Birds.” LBBs. But most finches sport some color; vibrant colors in some cases. The most common hues are yellow, red, and orange. A smaller number of species have blue or green patches of feathers. The latter group includes most of the Euphonias and the Chlorophonias of Latin America.
The bills of most finches are fairly short; downright stubby in some species. Finch bills are cone-shaped, deep, and pointy at the tip. Sure, there are some exceptions, but that’s the typical shape.
These conical bills are superbly well-suited for cracking open the shells of seeds. And finches are all about seeds. Seed-eating creatures like these are called granivores. The diets of finches are more vegetarian than most other songbirds. They eat almost exclusively seeds and berries all year long.
Finches generally have voices that we humans find pleasant to listen to. The male songs tend to include chirps, rapid trills, and musical, liquid notes.
The most commonly observed species in North America is the House Finch, Haemorhous mexicanus. House Finches are streaky brown birds. The male has a wash of red on his head, throat, and breast. Another common species in North America is the American Goldfinch, Spinus tristis. These are really small birds, at about 4.5 inches or 12 centimeters long. Males of this species are lemon yellow with a jet black cap and wings.
Zipping across the Atlantic, we can check out some of Europe’s finches. How about the European Goldfinch, Carduelis carduelis. This bird has a similar shape to the American Goldfinch (song), but it’s a somewhat smaller bird. Note that these two species are not in the same genus, which means they’re not super closely related, even though that’s what their common names suggest. This Goldfinch has some pretty jazzy plumage. It has a bold pattern of red, white, and black on its head, a tan body, and black wings with yellow and white highlights. I think it's a really striking, cool-looking bird.
The Citril Finch (song), Carduelis citrinella, is in the same genus as the European Goldfinch. Its colors are more subtle, being mostly grayish with soft yellow accents. One more European bird, the Common Chaffinch (song), Fringilla coelebs, is, true to its name, a very common species. This handsome bird has a blue-gray sort of hood or mantle, with a soft pink-ish orange face and body.
To get a taste of something a little further afield, let’s go all the way over to the far east of Russia. Siberia is the home of the Long-tailed Rosefinch, Carpodacus sibiricus. This medium-sized finch has—surprise surprise—a long tail. And its bill is rounded and stubby, sort of like the Eurasian Bullfinch (song). The Long-tailed Rosefinch is gray-ish brown overall, but it has some striking crimson-colored markings on its head and neck. It's got patches of pale pink on its body as well.
The Chestnut-breasted Chlorophonia (song), which has the scientific name Chlorophonia pyrrhophrys, is found in the cloud forests of South America. It’s a small, short-tailed bird, and it’s about as colorful as you can get for a species in the family Fringillidae. Males and females are both bright blue and green overall, but the male has a little more pizzazz. He’s got yellow on his sides and a reddish belly. This is a gorgeous bird.
Family, Distribution, Evolution
Family
We’re focusing today on a biological family; Fringillidae. But if we climb up one rank or level in our classification system, we have the order Passeriformes. The family Fringillidae is one of about 140 families nested within the order Passeriformes. There are over 6,000 bird species contained in this order. As a group, we call them ‘songbirds.’ At least half of all bird species on the planet are songbirds.
The name of the family Fringillidae comes from that cool genus name. Tracing the etymology of the word Fringilla way, way back to the early Indo-European language, it meant “to make a small noise or twitter.” This evolved to mean “small bird” in Classical Latin. And then it came to be the word for “finch” in later versions of Latin.
Today, we humans have the honor of sharing the planet with about 210 species of finches. So this is a pretty species-rich family. Over half of these species belong to only four genera. For example, the genus with the most finch species is Crithagra. The 37 species in the genus Crithagra are African birds… the seedeaters, canaries, serins, and citrils.
If we look for the region with the highest level of finch species diversity, the continent of Asia wins the trophy, with 74 species. Of course, we also find some of those same species in Europe.
Within the family Fringillidae, there are three distinct subfamilies. A subfamily is a level of classification sandwiched between family and genus. These subfamilies are evolutionary lineages or branches that might someday evolve apart—or diverge—so much that they each become a full-blown family.
So briefly, the three subfamilies are Carduelinae, Euphoniinae, and Fringillinae. Not Fringillidae, but Fringillinae. The Carduelinae subfamily contains the vast majority of finch species, over 150. So this includes most of the familiar species.
The subfamily Euphoniinae contains those colorful Euphonias and Chlorophonias from Mexico, Central America, and South America. This group of 32 species was once placed in the tanager family, Thraupidae. Unlike nearly all other finches, Euphonias and Chlorophonias have glossy feathers. Overall, these little dudes just don’t fit the image of your standard finch. But the genetic data doesn’t lie, and that is what helped ornithologists figure out that these birds are actually finches.
The last subfamily is Fringillinae, which contains only four Eurasian birds, which are the three different chaffinch species plus the Brambling.
A group of finches that deserve special mention are the Hawaiian Honeycreepers. In fact, I plan to do an entire blog on these birds and the other avian fauna of Hawaii… at some point.
The honeycreepers of Hawaii are an amazing group of 18 species in the Carduelinae subfamily. Many of them look nothing like your typical finch. Some have long, downward-curving beaks and bright red or yellow plumage. These birds are so un-finch-like that they used to be placed in their own family. Later, they were reclassified and mobbed to a unique subfamily within the family Fringillidae. Now, thanks to recent genetic analyses, we know they actually belong to the Carduelinae subfamily.
Distribution
The many weird and wonderful Hawaiian Honeycreepers all evolved from a single lineage of rosefinch from Asia. These birds represent one of the most spectacular examples in biology of an adaptive radiation. Darwin’s Finches are another classic example.
Recall that adaptive radiation is where a one lineage diversifies through evolution into multiple species to fill a bunch of ecological niches. Hawaiian Honeycreepers colonized then spread across the remote island chain. They evolved into over 50 species over millions of years. Some came to specialize in feeding on flower nectar, some were insectivores, some were seed-eating granivores, and so on. Sadly, humans have caused the extinction of many of these honeycreepers. Only 18 species are left today, and most of them are in serious trouble. We’ll look at their full story when I make a blog on the birds of Hawaii.
As a family, Fringillids, our 210 species of true finches, are spread across most of the planet. Some are in the tropics, others live well above the Arctic Circle or way down to the tip of South America. You’ll find finches on all the continents except Australia and Antarctica. Finches are also absent from the South Pacific, including New Zealand. Who knows why they aren’t naturally found in Australia or New Zealand?
Notice I used the qualifier “naturally” there. We humans have done our usual trick of shuffling species around, dropping them off in places where they don’t belong. For example, even though there are no naturally occurring, native finches in New Zealand, today you can find 5 species there. These include the Common Chaffinch, the European Goldfinch, and the European Greenfinch.
In North America, our most common species, the House Finch, is found across most of the continent. But originally, it was a bird seen only west of the Mississippi River. In the early decades of the 20th Century, some marketing genius decided to sell House Finches as cage birds in New York City, calling them “Hollywood Finches.”
This sort of nonsense went on even after 1918, when the Migratory Bird Treaty Act made the sale of House Finches and other wild birds illegal. There was actually a secret trading ring that shipped about 100,000 House Finches from California to New York.
Eventually, the law started to crack down on these bird-peddling shysters. Pet shops and bird traffickers started to set their House Finches free out of fear of being busted. Starting in the 1940s, some of these recently liberated birds began to breed in New York. Over just a few decades, they spread across most of eastern North America.
Oh, and people released some House Finches in Hawaii, too. So the Aloha State is also crawling with introduced House Finches.
If we return to look at just the natural distribution of the family Fringillidae, we find there are many habitats used by these birds around the world. Most finches are birds of woodlands, forests, and scrub habitats. But some live in more open environments like savannas, alpine slopes, and deserts. There’s even a species called the Desert Finch, Rhodospiza obsoleta. This sand-colored bird lives in arid parts of the Middle East and Central Asia.
Evolution
Well, we don’t have too many well-preserved fossils of these birds. Apparently, one challenge with fossils is that over the course of the last 65 million years, multiple, independent bird lineages have evolved a finch-like beak and skeletal structure. So if you have just a fossil, you might not be able to say for sure that it belongs to a species in the family Fringillidae.
Genetic data to the rescue! Genetic data calibrated with a molecular clock gives us a rough estimate of when finches probably burst onto the global scene. It looks like the origin of the family Fringillidae was somewhere in Eurasia, 10 to 20 million years ago.
Fringillidae is one of the most-recently evolved bird families in the world. That’s why you find these birds way at the back of your field guide. This is true at least for field guides to birds of North America, Europe, or Asia. As I mentioned earlier, modern field guides are typically ordered taxonomically. The more ancient-slash-primitive bird groups are in the front; more recently evolved groups are toward the back. Ducks and geese, for example, are in the first pages because those birds belong to what we know is a super old branch of the avian tree of life.
When I’m learning about a family of birds, one of the things I really want to know is: what birds are the closest relatives of this family? The best answers usually come from genetic research published in the last 10 to 15 years. As I’ve already been pointing out, data from bird DNA reveals the relationships among different types of birds that we might not be able to detect if we looked at only their anatomy or behavior.
So, who are the closest relatives of our finches? This one is a little tricky to answer. Finches and their close relatives have evolved so recently that the lineages of these birds are a little difficult for ornithologists to disentangle. But what we can say is that, 10-20 million years ago, the family Fringillidae split off from another lineage that includes several families of familiar songbirds, mostly from North America. These include the cardinal family, New World blackbird family, New World Warbler family, and tanager family. So these are all pretty close relatives of finches.
There’s one more thing I want to tell you regarding the evolution of finches. In researching this blog, I came across an interesting scientific paper that offers us a little more insight into this group of birds. The research was conducted by a group at the National Museum of Natural History in Brunoy, France. It was published in 2017, in the journal Ecology and Evolution.
The researchers analyzed 53 behavioral and anatomical traits from across 81 species in the family Fringillidae. These traits included things like migration behavior, diet specialization, typical numbers of offspring, and so on. The researchers wanted to test some ideas about how these traits evolve differently in stable environments like tropical forests vs in highly seasonal, unpredictable places like the far northern latitudes.
They concluded that finches have evolved several ways of life—several strategies—that correspond with different environments. Some suites of finch traits work well in strongly seasonal, harsh environments like the far north; other traits are beneficial in relatively easy-going, benign places like equatorial jungles.
In the “Barbarian” strategy the finches are gregarious; they travel in flocks, roaming far and wide. These barbarian finches also raise relatively large numbers of babies each year. And their males and females look more or less the same. So there’s not much sexual dimorphism.
Based on this research, it looks like the earliest finches from millions of years ago were probably of the barbarian sort. That’s the ancestral strategy. But plenty of finch species still live this way today. The barbarian way of life works well in challenging environments like the boreal forests of North America and Eurasia. The Common Redpoll, European Goldfinch, and Pine Siskin are examples of species that fit into this category. These guys travel around in nomadic flocks, they often produce two or more broods a year and therefore crank out lots of babies, and their sexes look very similar.
The alternative taken by many finches is the so-called “Civilized” strategy. These birds have evolved in places where life is far more predictable. Places like the tropical lowlands of South America, where the climate is stable and food is plentiful. Civilized birds don’t need to roam around so much to look for seasonally or sporadically available food. Instead, they tend to set up and maintain territories. They’re also less gregarious. And because they can devote more time and energy to each of their babies, they don’t need to crank out so many of them. Barbarians, on the other hand, raise more chicks and broods every year because life for them is hard and fewer are likely to survive. Barbarian chicks have to face the cold, hard reality of life at a young age.
Several of the Euphonia species of South America fit nicely into the ‘civilized’ category. These dapper little birds set up territories and don’t move around much. They’re not super gregarious. And they raise only a few offspring each year. Compared to their frenetic barbarian cousins, Euphonias live a slower paced life. I’ve only given you a simplified summary of this research, because there are more details and nuances that we don’t have time to get into.
Conservation
Let’s take a few moments to consider the conservation status of finches around the world. Looking at the IUCN Red List, which is the best resource for this kind of information, we see that 42 species in this family are classified as being in some sort of trouble.
12 are critically endangered, 11 are endangered, 13 are vulnerable, and 6 are near threatened. Most of the seriously imperiled finches on the planet are concentrated in one small geographic area: Hawaii. Of the 12 critically endangered species, 11 are in the Hawaiian Islands.
And what’s really sad is that 17 of the 18 finch species that have gone extinct in the last few hundred years were also native to Hawaii. These birds were wiped out by humans, of course. Factors include the destruction of Hawaii’s forests; the introduction of pigs, rats, and other invasive mammals; and the accidental introduction of mosquitoes carrying avian malaria. Again, this story deserves a whole blog.
In Europe and elsewhere, many finch species have been captured in the wild to be kept as pets in cages. This has been going on for thousands of years, since Roman times and before. Cage birds were all the rage in Victorian Britain. That led to hundreds of thousands of wild finches being captured in the 1800s.
The trade in cage birds has often been devastating to finch populations. For example, the Red Siskin, Spinus cucullatus, is an endangered species in northern South America. Males of this species are beautifully colored in red and black. Decades of heavy exploitation for the pet trade has pushed the Red Siskin close to extinction in the wild.
Sometimes, finches have been targeted directly for persecution. For example, the Eurasian Bullfinch was, until not that long ago, killed by the thousands in England and elsewhere. Why, you ask? Who would do such a thing? Well, I guess people who own fruit tree orchards. You see, Bullfinches love to eat the buds of fruit trees. Some of those trees are grown commercially, like pears and cherries. For hundreds of years, parishes all over England actually paid a bounty for every bullfinch killed.
But here’s the thing: all of this carnage was probably unnecessary. Some research shows that those fruit trees can lose up to half of their flower buds and still produce just as much fruit when harvest time comes around. So all those poor little bullfinches may have died for no reason. I mean, I think it's horrific to kill them in any case. Apparently, it’s still possible to get a license from the British government to kill bullfinches.
Diet and Foraging
As I mentioned earlier, the diets of finches are more plant-based than those of most songbirds. All year long, finches are out there eating seeds, berries, flower buds, leaves, and so on.
The reason this is noteworthy is that most other songbirds that eat seeds and berries in the non-breeding season switch to eating more insects and other invertebrates when it’s time to raise a family. For example, this is the method of operation for many New World sparrows, like the Dark-eyed Junco and White-crowned Sparrow. Such birds also feed mostly invertebrates to their chicks. This makes sense, because invertebrates are rich in protein. Producing eggs requires a lot of protein, and a growing chick needs a lot of protein.
But birds like our beloved little American Goldfinch just keep on chowing down on seeds in the breeding season. They’re granivores through and through. American Goldfinches are especially fond of thistle seeds. They even feed seeds—and only seeds—to their babies. Finches like this have evolved the ability to get all the protein they need from seeds alone.
In a previous blog post, we looked into the weird world of brood parasites. These are birds that drop their eggs off into the nests of other species. Brood parasites trick other birds into raising their babies. In North America, our best known brood parasite is the Brown-headed Cowbird. Well, when a cowbird drops an egg into the nest of an American Goldfinch, it has made a big mistake. The cowbird egg hatches and the unsuspecting goldfinches start to take care of the hatchling cowbird as if it were their own offspring. So far so good for the cowbird. The baby cowbird begs for food and the goldfinches oblige by stuffing it full of thistle seeds. But within a few days, the cowbird chick dies. It just can’t survive on a diet of nothing but seeds.
Like the American Goldfinch, House Finches, European Goldfinches, and a whole bunch of other species are similarly granivorous. This is especially true for the many members of the Carduelinae subfamily.
The European Goldfinch is another connoisseur of thistle seeds. Recall that both the genus and species name for this bird is Carduelis. This name actually comes from the Latin word for ‘wild thistle.’ So the bird was named after its favorite food.
Not all finches are so laser-focused on seeds and berries. The Common Chaffinch has the most varied diet of any bird in this family. It eats mostly small insects and only supplements its diet with seeds. Interestingly, chaffinches are also the most ancestral or primitive of all the living finch species. They’re on a little branch of their own at the base of the finch family tree. Remember that the three chaffinch species plus the Brambling make up the Fringillinae subfamily.
As a quick aside, one of my favorite finch experiences was when I found and photographed a Blue Chaffinch (song) on Tenerife, which is one of the Canary Islands. They’re part of Spain, but located off the northwest coast of Africa. I was on my own, exploring the islands, and I really wanted to find that bird. It's endemic to Tenerife, meaning it's found nowhere else in the world. Finally, I spotted a blue chaffinch singing in some pine trees. I spent some quality time appreciating it and snapping photos. I was in heaven. The photos didn't turn out so great, but I treasure the memory.
The diets of birds in the Euphoniinae subfamily differ from the diets of the more typical finches. Euphonias and chlorophonias are fruit-eaters. They’re frugivores more so than granivores. Most of them are crazy about mistletoe berries. And some eat figs and cultivated fruit like bananas and oranges. They even regurgitate fruit to feed their chicks in the nest.
Okay. Let’s talk about the Beak of the Finch, the actual anatomical structure of the finch’s bill. The classic cone-shaped bill of a finch is specially adapted for cracking open the shells of seeds. Here’s how it works…
A finch grabs a seed and holds it between the upper and lower parts of its bill. We call these the upper mandible and the lower mandible. The bird uses its tongue to keep the seed in place and manipulate it if necessary. The upper mandible has a concave groove running along its edge. The lower mandible has more of a sharp edge, like a knife. With the seed firmly in place, the finch bites down while moving its lower mandible back and forth in a sawing or slicing motion. The shell cracks and out pops the tasty kernel from the inside. The kernel gets scarfed down, and the shell is tossed to the ground.
The next time you’re near a bird feeder and there are some finches around, try to watch them cracking seeds this way. It happens really fast!
The sizes and shapes of finch beaks correspond with the type of seeds they eat most often. Some have longer, pointy bills; others have big, thick bills, and so on.
The thickest bills belong to the 15 finch species we call grosbeaks. This word comes from French and means ‘fat beak.’ We have the Evening Grosbeak, Japanese Grosbeak, and Pine Grosbeak, to name a few species. The 15 grosbeak finches are not all in the same genus, which means they aren’t all closely related. Because it turns out that big, fat beaks have evolved independently more than once within the Fringillidae family.
Finches with fatter bills can bite with more force, so they can crack the shells of bigger seeds. Sometimes small finches like siskins and redpolls will hang out around a big, burly grosbeak to see if they can score any table scraps. The little birds can’t crack the big seeds themselves, so they wait for the grosbeak to do it.
There are some splendid examples of beak specialization in the finch family. The Hawaiian Honeycreepers are the most extreme, with all sorts of outlandish bill shapes that correspond to their respective diets. Some slurp up flower nectar, others catch insects, etc. Compared to most finches, these honeycreepers are in a league of their own in terms of dietary specialization.
But just as spectacular are the 6 crossbill species found in North America and Eurasia. These finches—all in the genus Loxia—have amazing bills that are unique in the world of birds. The curving tips of their upper and lower mandibles cross each other in the horizontal dimension. It’s sort of like when you wish for luck and cross your fingers, when your middle finger overlaps your index finger. No other birds in the world have beaks like this.
Crossbill beaks are designed for eating the seeds of coniferous trees, such as pine, larch, and spruce. A crossbill twists its lower mandible to pry apart the scales on a cone, then it uses its tongue to grab the seed tucked between the scales. The different crossbill species specialize in eating from different types of cones. For example, the White-winged Crossbill, also known as the Two-barred Crossbill, eats mostly the seeds of larches. The Cassia Crossbill, on the other hand, specializes on Lodgepole Pine.
One feature shared by most finches is that they feed while climbing around in bushes, trees, or on flower stalks. This is in contrast to, say, sparrows, who tend to forage for seeds on the ground.
Finches have short legs and strong, grippy feet. These are great for clinging to plants, even while hanging upside down. Crossbills clamber around in the needles of conifer trees, Euphonias gobble mistletoe seeds in the branches of tropical hardwoods, and goldfinches ride on the stems of swaying sunflowers and thistles. There’s a lot more I could say about the diets of finches and how they eat.
Movement and Migration
When it comes to their annual movements, across the seasons, many finches don’t show the strong migratory behavior we see in other familiar songbirds like warblers. Finches are more often facultative migrants, flying long distances only when their food supplies run thin. Many finches are resident birds, while others are nomadic. Nomadic species like Evening Grosbeaks, crossbills, and siskins wander around in flocks searching for their sporadically available food sources.
This brings us to the concept of irruption. This is a form of irregular migration where birds show up in places we don’t normally see them. The word irrupt comes from Latin, meaning “to break into or burst into.”
In northern winters, seed crops or other bird foods are scarce in some years. Some birds like finches and Snowy Owls move south in droves to find food. These birds come bursting onto the scene in lower latitudes and birders across the land rejoice. Birders love irruptions.
An outstanding irruption has actually occurred this winter here in North America. Trees in the boreal forests of Canada and Alaska have failed to produce many seeds. This happens every few years. It’s a sort of boom and bust cycle. The dearth of seeds this winter has forced all of our northern finches to fly southward into the US. Ornithologists are calling this event a “superflight,” because so many species are involved. This irruption includes Common Redpolls, Hoary Redpolls, Evening Grosbeaks, Pine Grosbeaks, Pine Siskins, Red Crossbills, White-winged Crossbills, and Purple Finches.
Breeding
Finch pairs are monogamous and both parents take care of the young. Male finches are often more brightly colored than females. In many species, like the House Finch, the red or orange feather colors come from carotenoid compounds found in seeds. The redder a male House Finch is, the more high-quality food he’s probably eating. Female House Finches prefer to shack up with the most brightly colored males. Ornithologists think that this is an example of plumage color representing an honest signal of the male’s fitness. By choosing a bright red male, a female is choosing a healthy partner with good genes.
The typical finch’s nest is a classic cup-shaped structure. However, Euphonias and Chlorophonias make dome-shaped nests with a little side entrance. In all finches, the female is the one who builds the nest and incubates the eggs. But dad sticks around to help feed the chicks.
The nests of House Finches in Mexico City are often littered with cigarette butts. What’s up with that? There’s an actual research paper about this phenomenon published in the Journal of Avian Biology. What happens is female finches collect cigarette butts off the street, tear them up, and line their nests with the fibers. The researchers in this study figured out that the cigarette butts are added by the birds as a response to the presence of ticks, which are nest parasites. Apparently, the nicotine and other toxic chemicals in cigarettes repel the ticks. Crazy, huh?
Nestling finches fledge and pop out of their nests after 10 days to a month, depending on the species. The young birds are cared for by mom and dad for a couple weeks, at least for most temperate species. Some Hawaiian Honeycreepers take care of their offspring for up to a year.
Once they’re on their own, finches face the many challenges of being a small songbird. They have to find enough food, endure seasons of harsh weather, and avoid predators and diseases. Most won’t survive more than a few years. But a lucky finch can live for over 10 years and leave behind a handful of offspring. That’s at least 10 years to crack countless seeds, destroy fruit tree orchards, overwhelm your bird feeders, collect cigarette butts, or sweep across the land in a horde of tiny, feathered barbarians.