This adorable t-shirt design features four of our Birdorable birds that are common in back yards across the United States and Canada. The birds that are perched together in this original cartoon design are: American Goldfinch, Northern Cardinal, American Robin and Black-capped Chickadee.

Cute Backyard Birds is available on many different t-shirt styles and colors for men, women and children. The shirt shown above is a Girls' Fine Jersey T-Shirt, a super-soft ribbed collar shirt made of 100% combed ringspun cotton.

These shirts will make a great gift for anyone that loves their backyard birds! Click through to Zazzle to customize and order yours today!

Did you know that some species of bird feed their chicks milk? It's true, but it's not the same kind of milk that mammal mothers feed their young.

This baby bird food is secreted from the lining of the parent bird's crop and then regurgitated to the baby birds. It is high in protein and fat as well as other components important for their growing chicks to consume, like anti-oxidants, ("good") bacteria, and substances to improve the immune system.

All species of pigeons and doves feed crop milk to their young -- for these species the substance is called pigeon milk. Flamingos also feed their young a type of milk, though production occurs in more of the upper digestive tract than just the crop. Male Emperor Penguins produce a similar substance to feed their chicks when the mother bird is away at the time of hatching.

In pigeons and doves, parent birds begin to produce the milk days before their eggs hatch. The chicks, called squabs, eat only crop milk for the first week after hatching. Afterwards other foods are introduced, after being softened inside the parent bird's crop.

This week's featured t-shirt design is our Birdorable Kakapo in BOOOOOM!!! which is shown here on a Kids' Basic Long Sleeve T-shirt from Zazzle. The model shown above is 4'7" and is wearing a small.

The critically endangered Kakapo parrot (or Owl Parrot) of New Zealand is the only flightless species of bird to use a lek breeding system for mating. During part of the lekking process, males compete for females by displaying and making a "booming" sound. Boom! Males position themselves kilometers apart to signal to potential mates.

This fun and original Birdorable design is inspired by the booms of the lekking Kakapo. Pick this up for the Kakapo lover on your list! Only true Kakapo fans will "get" this unique and cute cartoon design.

Earlier this month, the Iiwi ('I'iwi), a beautiful Hawaiian finch, was introduced as the American Birding Association's Bird of the Year for 2018. We think it's an interesting and excellent choice!

In 2016 Hawaii was added the ABA Birding area by popular vote, and the process of adding species to the official checklist was completed last year. So it makes sense to feature a Hawaiian species in 2018.

The Iiwi is a type of finch, part of a group of Hawaiian honeycreepers. More than 50 species of honeycreeper used to call Hawaii home. Today less than half of those species still exist. They face threats including predation by introduced species and competition from invasive birds, as well as habitat loss and disease.

Of the native birds of Hawaii, the Iiwi is the most common.

The beautiful Iiwi can be recognized by its bold scarlet and black plumage, and by its long curved bill. In many ways the Iiwi behaves like a hummingbird, hovering in flight and drinking flower nectar.

Be sure to visit the ABA's Bird of the Year page to learn more about the Iiwi!