Today we'd like to share with you the meaning of the term altricial, especially as it relates to birds. It is the opposite of a term we shared earlier on the blog: precocial. Let's learn about what it means to be altricial!

The term altricial comes from the Latin alere, which means "to nurse, to rear, or to nourish." An altricial species is one in which the newly hatched or born young need to be cared for by their parents for an amount of time. While a precocial animal may be mobile and relatively independent within days or even hours of being born or hatched, an altricial species must rely on its parents to survive for a period of weeks, months, or even years before it is independent.

In birds, this means youngsters come out of the egg almost completely naked. They are relatively immobile, needing to stay in their nest, and some have closed eyes as well.

While having helpless babies may seem to be a disadvantage, there are advantages to this breeding strategy. Altrical eggs are smaller, relatively speaking, than precocial eggs, resulting in less biological stress to mother birds. Precocial animals are born or hatched with brains relatively large compared to their body size, but don't grow much as they mature. Altricial species are born or hatched with smaller brains which grow as the animal matures. In general, altricial species therefore "have a wider skill set" when they reach full maturity.

Most songbirds have altricial young, as do owls, hawks, herons, and woodpeckers. Rodents, cats, dogs, and humans also have altricial young, which rely on their parents for the first few weeks or decades of life, depending on the species and individual young.

Celebrate owls with us on this #InternationalOwlAwarenessDay! This commemorative holiday is meant to raise awareness and spread knowledge of all of the birds in the owl family.

Did you know that there are over 220 recognized species of owl in the world? The smallest owl is the Elf Owl of North America; the largest owls are the Eurasian Eagle-owl and the closely related Blakiston's Fish Owl. You can find two of these species among our Birdorable collection of 13 owls.

Happy International Owl Awareness Day! What is your favorite species of owl?

The Ridgway's Hawk is a Critically Endangered bird of prey endemic to the island of Hispaniola. Since 2002, the Ridgway's Hawk Project has been fighting to save this species in the Dominican Republic. The program involves several components, including research, assisted dispersal, and education.

The town of Los Limones is located outside of Los Haitises National Park, where the Project has been working with the community for almost 20 years on Ridgway Hawk conservation. As a part of the Project's outreach, a local youth baseball team was named Los Gavilanes, to honor the species, Gavilan in Spanish. Friends of the Ridgway's Hawk Project donated uniforms to the kids, which feature a Birdorable profile image of the namesake species!

From our friends at the Proyecto Conservación del Gavilán de La Española, we would like to share these photos of Los Gavilanes baseball team.

When most people think of owls, one of the facts that often comes up is that they are nocturnal. Nocturnal animals are most active during the night, sleeping by day. While most owl species are nocturnal, not all are. Adaptations found in nocturnal animals include enhanced eyesight, hearing, and sense of smell. Besides owls, other bird species known for being nocturnal include the Southern Brown Kiwi, the Kakapo, and the Common Nighthawk. Familiar nocturnal animals include bats, raccoons, and fireflies.

Diurnal animals are most active during the day, and sleep at night. For the most part, all animals first evolved to be diurnal. Nocturnal animals later evolved adaptations for being active at night in order to avoid predators and reduce competition with other species. Advanced color vision is an adaptation seen in diurnal animals. While most birds are diurnal, many species migrate at night, mostly to avoid predation. Animals known for being diurnal include most reptiles, pollinator insect species, and primates (including humans).

There are other terms to describe when animals are active:

• Crepuscular animals are most active during twilight hours, around dawn and around dusk. Examples of crepuscular birds include the Barred Owl and Chimney Swift.
    
• Cathemeral animals are active during spurts of time during the day and night. The activity is sporadic and occurs at irregular intervals. Cathermal animals are usually active during parts of both daytime and nighttime. Lions and some species of lemur are known for being cathermal.

On this date* in 1844, off the coast of Ireland, a pair of Great Auks were killed. These proved to be the last specimens of Great Auk ever collected.

The Great Auk was a flightless species. It stood up to 33 inches tall and weighed about 11 pounds. The Great Auk's scientific name, Pinguinus impennis, roughly translates to plump and flightless. The auk's black and white plumage was similar to that of penguins; penguins are so named after the auk's scientific name due to this similarity. Despite the physical similarities, the species (auks and penguins) are not closely related genetically.

Great Auks lived in the North Atlantic Ocean coasts, coming to land only for breeding. They nested colonially in areas close to favorable feeding grounds and away from predators like polar bears and White-tailed Eagles.

Although somewhat clumsy on land, Great Auks were agile in the water, able to propel itself underwater using its wings. It was also able to dive deeper and hold its breath longer than other alcid bird species.

Great Auks were once abundant. They were hunted as food by the Neanderthals more than 100,000 years ago. There are records of Great Auks being hunted more than 20,000 years ago in Spain, Italy, and France. While the Little Ice Age between the 16th and 19th centuries may have contributed somewhat to population losses for the Great Auk, it was massive human exploitation that ultimately doomed this species. Great Auks were hunted for their down and collected for their eggs, feathers, and skins.

Today there are 78 specimen Great Auks (skins) in museums and other collections. A Great Auk specimen sold to the Icelandic Museum of Natural History for £9000 in 1971; this was listed in the Guinness Book of World Records as the most expensive bird specimen ever bought and sold.

* Published sources are conflicted on the date; June 3 is also sometimes cited.

In most bird families, males and females both participate in the raising of their young. In 8% of cases, the female does everything related to care of eggs and raising offspring. And in just 1% of bird species does the male do all of the work -- after the eggs are laid, of course.

Some species are polyadrous, meaning individual birds will have different mates during the same breeding season. In the case of the Spotted Sandpiper, females will often have two clutches, the first of which she leaves after the eggs are laid. It's up to her mate to incubate the eggs and rear the chicks. She will then find a new mate and help to raise her second clutch with the new male.

Emus exhibit similar behavior, though male Emus go through a more extreme experience during incubation. During the approximate 8-week period, he does not leave the nest for any reason. He may lose up to a third of his bodyweight while he forgoes eating, drinking, and even defecating, standing up only to turn the eggs. Once the chicks are hatched, father Emu will protect his young for up to seven months, which is about how long it takes for them to fully grow. The group may stay together as a family for up to two years.

The paternal (father) duties of the Emperor Penguin are widely known. After the female lays the pair's one and only egg, she carefully transfers it to the male. And then she leaves him for two months. While she is out to sea, feeding, the male remains behind, incubating their egg between the brood patch on its underbelly and its feet. When the egg hatches, the male may have been fasting for over 100 days since he first arrived at the breeding colony. Once his mate returns, she cares for the chick so the male can finally go to the sea to find food.

Hornbills have an unusual breeding strategy that involves the female being practially sealed inside the nest cavity with the eggs, with only a small slit left open. This small opening allows the male to transfer food to his mate and to the chicks, once they hatch. During incubation and the hatchling phase, the family relies entirely on the male to provide food. The mother and chicks only leave the nest once they are too large to remain inside.

Happy Father's Day to all of the dads out there, avian and otherwise!

World Parrot Day is celebrated this year on May 31, 2019. The first World Parrot Day was in 2004.

The event was initiated by the World Parrot Trust as an opportunity to highlight threats to wild and captive parrots around the world. Actions that began on that first World Parrot Day led to the eventual ban of wild bird imports into Europe.

Oology is the study of bird eggs. It also refers to the study of bird nests and breeding behavior. Oology can also refer to the hobby of egg collecting, which is illegal in many locations.

Early scientific ornithological study often involved collecting birds by shooting them to study their anatomy and plumage up close. It also involved the collection and study of their eggs. Scientists studying the difference between samples of Pergrine Falcon eggs over time were able to identify DDT usage as the cause of a decline in raptor populations in the 1960s and 1970s.

Egg collecting as a hobby remained popular as the scientific value of this type of study declined. This was extremely popular especially in the United Kingdom, though the hobby was denounced by the British Ornithologists' Union as early as 1922. Although UK laws have made the amateur hobby collection of eggs illegal since 1954, oologists continue to pursue the hobby by collecting eggs. Egg collecting is illegal in many other jurisdictions as well, including the United States.

Read more:

• Not Birdwatching, bird(crime)watching!
• The egg snatchers
• Egg society denies aiding nest thefts

Traditionally, April Fools' Day is a time to play pranks, share hoaxes, and tell jokes. April Fool stories published by newspapers and other media outlets may trick readers into believing tall tales -- until they realize the date. Here are some bird-themed funnies that have come out on April Fools' Days in the past.

A lot of April Fool jokes involving crazy bird stories originated from photo manipulation -- an old-fahsioned version of "photoshopping". Examples of this include a German paper exposing a penguin as tall as a man in 1931; that time in 1941 when a newspaper revealed a military plan to plant bombs on crows; and the strange and silly rare human-legged ostrich that reportedly puzzled scientists in 1953 Australia.

Google is known to reveal a prank each April Fools' Day, often involving a new product or service in their technology offering. In 2002 they introduced PigeonRank to the world, exposing the truth behind their search technology. Pigeon Clusters (PCs) were the true power Google used to rank and sort web pages. The somewhat elaborate story behind PigeonRank was shared in detail, including graphs and diagrams and a FAQ.

A popular video was released by the BBC in April Fools' Day 2008 which showed Adelie Penguins taking flight. At the time it was one of the most viewed internet videos.

A mysterious physical April Fools' Day prank was played on the town of Portage, Wisconsin in 2012. Plastic lawn geese dressed in different outfits were placed around businesses, homes, and services in the city. In all, 132 geese were found. Although the perpetrators were not made known, no one who received a goose seemed to mind. Read this extremely wholesome newspaper report on the incident.

Then there was that time when we revealed a new species of crane that was discovered in South America. We even shared a colorful Birdorable image of the new species, which we dubbed the Painted Crane (Grus pictus). This April Fool prank came out just as we were celebrating Crane Week -- it was an incredible coincidence!

Watch out for more pranks and hoaxes as you go about your day and keep in mind the date! Happy April Fools' Day!

Allopreening refers to one animal preening another. While preening and grooming are usually individual actions, in some species, birds or animals will preen one another. This occurs in birds as well as other classes of animal.

We previously mentioned allopreening when discussing vultures during Vulture Week in 2015. The post Glossary of Vulture Terms explained, in part, that "allopreening refers to social grooming between multiple individuals, often performed to strengthen social bonds."

Social bonds may not be the only reason that birds preen or groom one another. Allopreening is most common in species that tend to gather in large flocks. In these species, birds in frequent close proximity to each other are more likely to transfer parasites amongst the close-knit group. Allopreening in these species helps to keep pests like ticks under control.

Allopreening between mated pairs of birds occurs more often in species where both the male and female raise their offspring together. The preening ritual may help strengthen the longer-lasting bond. In mated pairs where the birds may be separated for a long period of time, allopreening is part of a greeting ritual. For example, this type of allopreening occurs when male and female penguins are reunited after a long incubation shift where one of the mates was feeding at sea for days or weeks.

Allopreening may also help to reduce conflict or tensions among large flocks or breeding colonies of birds. The social structure of the colony plays a large part in who receives preening and how much.