This week, we're celebrating gulls! There are about 55 widely recognized species of gull in the world. We'd like to share some of the extreme facts and interesting statistics found within this diverse family.

Smallest Gull Species
The Little Gull, weighing in at around 4.2 ounces (120 grams), is the smallest species of gull. Its length is  9.8 to 12 inches (25 to 30 cm).

Largest Gull Species
The largest gull species in the world is the Great Black-backed Gull, which weighs in at around 62 ounces (1750 grams), almost 15 times as heavy as the Little Gull. It's length is 2.1 to 2.6 feet (64 to 79 cm). 

The Longest Living Gulls
Gulls, particularly the large "white-headed" gulls, can be long-lived. The longevity record for the European Herring Gull is 49 years! The longest-lived wild Great Black-backed Gull was over 27 years old.

Cross-Species Parenting
The Black-headed Duck of South America is known to be a brood parasite of the Brown-hooded Gull. The duck lays eggs in nests of other birds (including other ducks and other gulls) and lets the nest-owners do the incubating! The ducklings are able to leave the nest just hours after hatching, making their escape without otherwise disturbing the nest. The Brown-hooded Gull or other nesting adult will continue to care for its own eggs and chicks.

Tale of the Tails
Most species of gull have a rounded tail. There are only three exceptions: the Sabine's Gull and Swallow-tailed Gull have forked tails, and the Ross's Gull has a wedge-shaped tail.

Longest Migration
Many species of gull are migratory. The Franklin's Gull may have the longest migration of all the gulls. They breed as far north as central Canada, and spend the winter as far south as Chile and Argentina.

Rare Gulls & Threatened Species
The Lava Gull of the Galapagos Islands is considered to be Vulnerable to extinction. The small population of less than 400 pairs is relatively stable but the species is probably the rarest of all the gulls.

The Black-billed Gull of New Zealand is considered to be Endangered. The population has been on a rapid decline since the introduction of invasive predators to New Zealand, like weasels and cats.

Other species considered to be Vulnerable to extinction are the Relict Gull of central Asia, the Saunders's Gull of eastern Asia, and the both the Red-legged Kittiwake and the Black-legged Kittiwake.

Most Abundant
The Ring-billed Gull was once hunted for its feathers. With protection the species has rebounded and is likely the most common species of gull in North America.

Night Vision
The Swallow-tailed Gull is a "black-headed" gull found in the Galapagos Islands. They are the only completely nocturnal gulls in the world! They feed on squid and fish that only come to the water's surface at night. In order to be able to see in the dark, the Swallow-tailed Gull has very large eyes -- larger than any other gull species!

The nine species of lovebird in the world all belong to the genus Agapornis, which is Greek for love (agape) bird (ornis). These small and colorful parrots are known for their social affection and strong pair-bonding between lifelong monogamous mates. Their beauty and natural personalities make some of them popular species in aviculture (pet birds). Here are some facts about the species in the lovebird family.

• Lovebirds are native to Africa. Eight species come from the mainland African continent, while the Grey-headed Lovebird is native to the island nation of Madagascar.
• Most lovebirds have a varied diet which consists of fruits, vegetables, and seeds. Some lovebirds also eat figs and insects. The Black-collared Lovebird has a special diet in the wild, feeding on local figs. This dietary requirement makes the species one of the least popular lovebirds in the pet trade.
• Lovebirds typically live from 10 to 15 years, but may reach up to 20 years in captivity.
• Lovebirds are cavity nesters. Females take care of nest building, bringing material to the nest either in their beaks or tucked into their tail feathers. Red-headed Lovebirds nest in termite mounds. Established feral Rosy-faced Lovebirds in Arizona nest inside cactus plants.
• Because of their popularity in aviculture, several species of lovebird have multiple color mutations. Some lovebird species have mutiple common names, like the Rosy-faced Lovebird, which is more commonly known as the Peach-faced Lovebird in the pet trade.
• Most species of lovebird are not considered to be threatened by conservation experts. Lilian's Lovebird and Fischer's Lovebird both have the status of Near Threatened. The Black-cheeked Lovebird has a status of Vulnerable, facing threats from the pet bird trade, loss of habitat, and changes in local agriculture practices.
• Lovebirds are among the smallest species of parrot. The Grey-headed Lovebird is the smallest of the lovebirds, measuring about 13 cm in length. Rosy-faced Lovebirds and Black-winged Lovebirds are the largest, measuring over 16 cm in length.
• In most species of lovebird, males and females have similar plumage and are difficult to tell apart (if you're not a lovebird). Three species of lovebird exhibit sexual dimorphism: the Grey-headed Lovebird (named after the male -- females are entirely green); the Black-winged Lovebird (males have red at the forehead that the female lacks); and the Red-headed Lovebird (the male has more red in the head than the female).
• Rosy-faced Lovebirds, known more commonly as Peach-faced Lovebirds in aviculture, are among the most popular of all pet birds. There are many different color mutations and understanding Peach-faced Lovebird genetics can be somewhat complicated.

Blue Jays are large, bold songbirds that live across much of North America. They are common throughout their range, which includes the eastern two-thirds of the continent. Here are some facts about this familiar and widespread species.

• There are at least four subspecies of Blue Jay accepted by most authorities. The Florida Blue Jay weighs an average of just 74 grams, while Northern Blue Jays weigh in at 92 grams or more. Plumage differences between the subspecies are subtle, with some birds showing brighter plumage than others. The other two subspecies are the Coastal Blue Jay and the Interior Blue Jay.
• Blue Jays are omnivorous. They feed on a wide variety of food items, including large insects, acorns, bird seed, frogs, carrion, eggs from other birds, berries, and more. They love peanuts!

Blue Jay by Martin Cathrae [CC BY-SA 2.0]

• Blue Jays are in the Corvid family, a group of birds that includes crows and ravens and is known for intelligence and curiosity.
• Blue Jays are generally year-round residents throughout most of their range. Birds may move seasonally depending on availability of food. But jays are also known to migrate in huge flocks around the Great Lakes and on the Atlantic coast. The reasons for this great movement is a mystery.
• Blue Jays are skilled mimics. They are able to impersonate the calls of other birds, including raptors. A Blue Jay may mimic the call of a Red-tailed Hawk or a Red-shouldered Hawk in order to frighten other birds off of feeders so the jay can eat in peace. Calling out as a raptor may also serve to determine if any actual predatory birds are in the area.
• Blue Jays are known to mob potential predators. A Blue Jay or a group of jays that finds a predator, like a bird of prey or a snake, will call out a warning to other birds. They will also chase or dive-bomb predators to get them to leave the area.
• Blue Jays can raise or lower their crests. A crest at rest means the bird is relaxed. A raised crest indicates agression or excitement.
• Adult male and female Blue Jays look alike. They have the same coloration all year.

Blue Jay gathering nest material by Amy Evenstad for Birdorable

• Blue Jays mate for life.
• The longevity record for a Blue Jay living in captivity is over 26 years. The record for wild Blue Jays is over 17 years. This is known via bird banding programs.
• Blue Jays are particularly susceptible to West Nile virus. The disease can deccimate populations locally, but recent outbreaks have not significantly affected the global Blue Jay population.
• The Blue Jay is the official bird of the Canadian province of Prince Edward Island.

Today, March 14, is traditionally celebrated as Pi Day -- because when the date is written 3/14, it represents the first three significant numbers of Pi. Pie day may be celebrated by eating pie, but since we like birds, today seems like a good day to celebrate the family of birds that has pie right in the name: Magpies!

There are three groups of true magpies. The four species of magpie in the genus Pica are the Holarctic, or black-and-white, magpies. The nine species of Oriental magpie are generally blue-green and are in the Urocissa genus and the Cissa genus. The azure-winged magpie belongs in the genus Cyanopica. Here are some fun facts about this group of intelligent and curious birds.

• Magpies belong to the Corvid family, which makes them closely related to birds like jays, crows, and ravens.
• The cartoon characters Heckle and Jeckle are a pair of magpies.
• There are several collective nouns used to describe a group of magpies, including "a gulp of magpies" and "a mischief of magpies."
• Magpies aren't the only birds with "pie" in their name. Another group in the Corvid family is the treepies. One bird in this group has a confusing name: the Black Magpie of Asia.
• Another bird with a confusing name is the Australian Magpie. This species isn't a magpie at all! Although its black-and-white plumage is very magpie-like, this species belongs in a different genus and is closely related to the Butcherbirds of Australasia.
• A recent taxonomical split may have added a new species of magpie to the list. The Azure-winged Magpie has an usual fragmented range with part of the population in southwestern Europe and part over in eastern Asia. Some ornithologists consider the two populations to be separate species, naming the European bird the Iberian Magpie.
• The Javan Green Magpie is the most endangered species of magpie. Endemic to Indonesia, it is considered to be Critically Endangered by the IUCN. Other endemic species of magpie include the Sri Lanka Blue Magpie, found only in Sri Lanka, and the Yellow-billed Magpie, found only in the U.S. state of California.

Sexual dimorphism refers to observable differences between males and females of the same species. In basic terms, it means that a male of a species is easily distinguished from a female. In birds this usually means differences in size or in plumage. It can also be noted in behavior differences and other traits.

Earlier on this blog we talked about the extreme sexual dimorphism in Eclectus Parrots, where males and females show extreme differences in their plumage: males are bright green while females are shades of red and blue.

Sexual dimorphism exists in most species of raptor. In birds of prey, males are often smaller than the females of the species. However, this is often difficult to discern in wild birds, especially if seen at a distance or when only one bird is present.

Many common birds also exhibit sexual dimorphism. Male ducks are often colorful, while females tend to be drab. You can see this in the common Mallard.

Mallard ducks by Connor Mah (CC BY-SA 2.0)

In songbirds, males may be brightly colored while females have a similar plumage with more muted tones, as seen in Baltimore Orioles, American Robins, Eastern Towhees, and Black-throated Blue Warblers.

Eastern Towhees: female (left) by Brian Henderson (CC BY-NC 2.0), male (right) by Dendroica cerulea (CC BY-NC-SA 2.0)

In other birds, like the Eclectus Parrot mentioned above, the plumage differences are extreme. Examples of this can also be seen in the Superb Fairywren of Australia, and the Sage Grouse.

Can you think of other bird species where the male is easily told apart from the female? Do you have birds like this where you live? What about birds that aren't sexually dimorphic? Can you think of species where male and females are impossible to tell apart by looking at them?

There are about forty different species of toucan, spread over five genera. These include toucans and their smaller cousins, aracaris and toucanets. Here are some fun facts about the toucan family.

• All toucans have colorful and extremely large bills. Despite their size, the bills are composed of a kind of spongy material, and are extremely lightweight.
• Having a large bill is beneficial in foraging for fruit -- the bird can grab a lot of food without moving its whole body. The oversized bill also helps the toucan regulate its body heat in the steamy rainforest.
• Toucans are cavity nesters, but they aren't able to excavate their own nest holes with much success. They use cavities excavated by other birds, like woodpeckers.
• The smallest birds in the family range from about 11 or 12 inches long (the Green Aracari or the Lettered Aracari).

Green Aracari by Sham Edmond [CC BY 2.0]

• The largest species of toucan is the Toco Toucan, which reaches 29 inches in length.
• Toucans are able to fly, but they have relatively short wings. They are resident birds within their range (they do not migrate), and tend to get around their forest canopy habitat by hopping from branch to branch.
• The Toco Toucan is the most well-known species of toucan; it is sometimes known simply as "Toucan" or "Common Toucan".

Toco Toucan by William Warby [CC BY 2.0]

• The Keel-billed Toucan is the national bird of Belize.
• Toucans are found in the Neotropics, meaning they are New World birds found in tropical habitat. They range from southern Mexico into northern parts of South America. They are also found in the Caribbean.
• The constellation Tucana, a group of stars in the Southern Sky, is named after the toucan. It was established by Dutch astronomer Petrus Plancius and was first published in 1598 in Amsterdam.
• We have three birds in the toucan family here. Check out our Birdorable Keel-billed Toucan, Birdorable Green Aracari; and Birdorable Toco Toucan!

We're celebrating Vulture Week because this Saturday, September 5th, marks International Vulture Awareness Day (IVAD). This commemorative day has been celebrated since at least 2009 and aims to highlight the importance of vultures and vulture conservation through education.

In today's post we're sharing some keywords that pertain to vultures. This vulture glossary also includes definitions that apply to other bird families, but are important topics to understand when learning about vultures.

Carrion

If you're going to be talking about vultures, you are inevitably going to be talking about carrion, because that is what most vultures eat. Carrion is the decaying flesh of a dead animal. Other scavengers that consume carrion besides vultures include eagles, opossums, coyotes, and some beetles.

Convergent Evolution

Vultures in the New World (the Americas) are not closely related to Old World (Europe, Asia, and Africa) vultures. Since many vultures of both types have similar features like bald heads and scavenger behavior, how can it be that they are not closely related? The answer is convergent evolution. Broadly, this refers to organisms evolving similar traits while lacking a common ancestor. Birds, flying insects, and bats are not related, but they have all evolved the capacity to fly. Similarly, vultures in both the Old and New Worlds have evolved special traits to help them specialize in feeding on carrion. With few exceptions, no matter their location, vultures fill a similar niche in the ecosystem.

Crop

The crop is an expandable part of the digestive tract of birds and some other animals. The muscular pouch, close to the throat, is used to store food before digestion. The full crop of the Lappet-faced Vulture can hold up to 3.3 lb of meat!

Gorge

Vultures are known to gorge themselves at feeding sites. They will eat until their crop is completely full, and then sit full, digesting their food. It is thought that vultures sometimes gorge themselves to the point of being unable to fly.

Kettle

A group of vultures in flight together, particulary soaring on thermals, is known as a kettle. Kettle may describe other birds flying in this way, including mixed flocks which may or may not have vultures.

Preening

Preening is the act of cleaning or grooming. Birds, including vultures, preen themselves to keep their feathers in top shape. Allopreening refers to social grooming between multiple individuals, often performed to strengthen social bonds. Black Vultures are known to take part in allopreening at roosting and feeding sites. Often allopreening concentrates on the head area, a spot that a bird cannot easily reach with its own beak.

White-backed Vulture Preening by Sascha Wenninger

Stomach Acid

Vultures have extremely corrosive stomach acid, which helps them to safely digest dead animals that may be infected with diseases and toxins. The stomach acid protects the birds from contracting and spreading disease. Gut bacteria in vultures helps them to withstand several kinds of toxins that may be found in decaying flesh.

Taxonomy

Taxonomy is a scientific system for naming and organizing living things which share certain characteristcs. The taxonomy of vultures can be confusing. New World and Old World vultures aren't closely related, despite their physical and behavioral similarities. Some scientists think that New World vultures are closely related to storks. With new advances in the study of DNA, sometimes single species are split into distinct species. The Long-billed Vulture was split into two distinct species: the Slender-billed Vulture and the Indian Vulture. The Yellow-headed Vulture was split into two species in the 1960s: the Lesser and Greater.

The big day is almost here! Tomorrow our Vulture Week will conclude on International Vulture Awareness Day!

We're celebrating Vulture Week because this Saturday, September 5th, marks International Vulture Awareness Day (IVAD). This commemorative day has been celebrated since at least 2009 and aims to highlight the importance of vultures and vulture conservation through education.

Vulture week rolls on with some cool vulture facts. These extreme facts show how diverse this amazing family of birds can be.

Largest Vulture
Among New World vultures, the Andean Condor and California Condor can both reach up to 48 inches in length, and weigh 26 pounds or more. In the Old World, the Cinereous Vulture reaches up to 47 inches in length. Female Cinereous Vultures may weigh up to 31 pounds!

Smallest Vulture
In the Old World, the Palm-nut Vulture has this record. They only grow to be about 24 inches long and weigh just around 3.5 pounds. The Lesser Yellow-headed Vulture is the smallest in the New World, reaching between 22 and 24 inches in length.

Vulture Longevity Records
The longest lived Eurasian Griffon reached over 41 years of age in captivity. A captive-raised Lammergeier lived to be over 45 years old. The Andean Condor is believed to be capable of living 50 years or more in the wild. A captive Andean Condor that lived at a zoo in Connecticut lived 79 years! The longevity record for a wild Turkey Vulture is over 17 years, while a wild Black Vulture reached over 25 years of age.

Most Abundant Vulture
The Turkey Vulture is the most abundant species of vulture in the world, with a population that probably numbers into the millions of individuals.

Turkey Vultures by docentjoyce (CC BY 2.0)

Fastest Decline
Many vulture species in Africa and on the Indian subcontinent are in peril. The population decline of the White-rumped Vulture is an unfortunate example of this. In the mid 1980s, the White-rumped Vulture was considered to be the most abundant large bird of prey in the world. Since that time, the species has declined rapidly, losing up to 99.9% of its total population in just 20 years.

Longest Migration
Most vulture species are sedentary, year-round residents throughout their range. In the New World, the Turkey Vulture is the only vulture spcies that has regular seasonal migration. Birds that breed in southern Canada probably travel at least 1,000 miles to reach their wintering grounds to the south, traveling around 100 miles per day of migration. In the Old World, Egyptian Vultures may travel up to 5,500 miles when they migrate from their breeding grounds to their wintering grounds at the southern end of the Sahara Desert.

Ancient Birds
Relatives of vultures have existed for millions of years. Early ancestors of Old World vultures, in the now extinct Diatropornis family, existed in the Eocene epoch about 56 to 38 million years ago.

Highest Flyer
The Rueppell's Vulture of Africa is thought to be the world's highest flying bird. It has been recorded flying at an altitude of 11,300 meters or 37,000 feet above sea level!

Can't get enough of these amazing and important birds? Be sure to check out our great collection of cute and original vulture apparel and gifts.

Owl eyes are pretty amazing.

They don't really have eye "balls" like humans and other animals. Instead, owl eyes tend to be more tube-shaped. Their elongated eyes are held in place by bones in the skull. Owl eyes are also relatively enormous when compared with human eyes. If a Great Horned Owl were the same size as a human, its eyes would be as large as a pair of oranges. In some owl species, the weight of the eyes accounts for up to five percent of the total weight of the bird.

Because of the shape of an owl's eyes, the bird is unable to move the eyes inside their head. They have to turn their heads around in order to look around. An owl can turn its head about 270 degrees, or about 3/4 of the way around. There are some special adaptations in owl anatomy that allow them to turn their heads so far, including extra vertebrae in the neck, and different blood vessels that keep blood flowing between the head and body.

Unlike many other bird species, owls have forward-facing eyes. This makes them appear more human-like than other birds and may contribute to their general popularity among people. Compare the forward-facing eyes on the Great Grey Owl's face to that of the American Bittern below.

Great Grey Owl by Rolf B. [CC BY-SA 2.0]

American Bittern by Amy Evenstad for Birdorable

Many owl species are nocturnal, but owls can see perfectly fine in the daylight as well as at night. Because of their excellent night vision, their pupils don't retract as much as in humans. Closing their eyelids halfway or more helps keep the bright light from hurting their eyes. This also gives owls the appearance of being sleepy in daylight, when in fact they may be fully awake and alert.

Owls have three sets of eyelids. Upper and lower eyelids close when the owl blinks or sleeps. A third, semi-transparent lid, called a nictitating membrane, closes diagonally across the eye. This thin layer of tissue is used to keep the eyes clean and to protect the eye while still allowing for some vision. You can see this membrane partially closed in the photo of a Barred Owl below.

Barred Owl with nictitating membrane visible by Philo Nordlund [CC BY 2.0]

The tanagers are a family of songbirds found across the Americas. These small birds tend to be colorful; often males are more brightly plumaged than females.

Tanagers in name only?

There are four species of tanager found in North America. These are the Western Tanager, Summer Tanager, Scarlet Tanager, and Hepatic Tanager. They are in the genus Piranga and are thought to be closely related to cardinals; they may not belong in the tanagers' Thraupidae family at all.

Colorful Across the Americas

In total there are over 200 species of tanager. Most are found in tropical habitats, and many species have relatively small native ranges. For example, the Green-headed Tanager is found along a narrow strip extending from southeast Brazil down into southeastern Paraguay and northeast Argentina.

Western is Most North

North America's Western Tanager is notable for being the northern-most ranging species of tanager. This migratory species breeds as far north as Canada's Northwest Territories. They spend the winters in Central America.

Hepatic: I'm Huge in South America

In the United States, the Hepatic Tanager is only found as a breeding bird in the southwestern mountains. However, the species has a very large native range and many birds are permanent residents across a large portion of South America.

Summer's Pretty Song

Most tanagers are not known for their pretty song, but the Summer Tanager is an exception. It sings a melodic tune that reminds many of the American Robin's song.

Cowbird's Target

The Scarlet Tanager is particularly susceptible to brood parasitism from Brown-headed Cowbirds. Being forest nesters, they never developed a strategy against the rogue-nesting cowbirds. Segmented habitat (due to human developement) means tanagers more often nest near open habitats favored by cowbirds, rather than deep inside old-growth forests where cowbirds rarely occur.

Ripe Old Age

The longevity record for wild Western Tanagers is nearly seven years; for wild Summer Tanagers it is nearly eight years; and for wild Scarlet Tanagers the record is nearly twelve years. These records were collected via bird banding.