Birders know that Cooper's Hawks and Sharp-shinned Hawks look alike. These two species share many of the same field marks, and can often be found in the same habitat, behaving the same way. However, they don't often appear in the exact same place at the same time. That's what makes a series of photos posted earlier this month on the Cornell FeederWatch blog truly remarkable. A staff member observed and photographed a Sharpie mobbing a Cooper's Hawk, and the results were pretty amazing: Sharp-shinned Hawk Versus Cooper’s Hawk. When you've just got one bird to identify, there are few key points to consider when trying to determine whether your bird is a Cooper's Hawk or a Sharp-shinned Hawk.

Size, head shape, and body proportions are among the important attributes to keep in mind in this identification challenge. This cute original design featuring a Birdorable Cooper's Hawk next to a Birdorable Sharp-shinned Hawk points out these tips and more. This new design is available on t-shirts and novelties for your accipter-studying convenience.

Many countries have an official national bird. For example, the national bird of Israel is the Hoopoe, and the national bird of Mauritius is the Dodo. All U.S. states also have official birds. But did you know that there are even some cities that have their own official bird?

The official city bird of Rauma, Finland is the Great Black-backed Gull. Oddly, in the Rauma dialect, there is no specific name for this species. The word "truut" is used for all large gulls found in the area: Great Black-backed; Lesser Black-backed; and Herring. It is estimated that the Great Black-backed Gull was nesting on Rauma soil 4200 years before the city was officially founded! For Rauma, the gull symbolizes the care that residents should take in local wildlife.

Great Black-backed Gull with the Rauma Coat of Arms

With their special water-resistant plumage, ducks are made for water. But did you know that several species of duck actually require trees when it comes to breeding? Some ducks are cavity nesters. We've recently added one of these cute little cavity-nesting ducks to Birdorable. The Bufflehead is one of the smallest species of duck to live in North America. They're just about 14 inches long, and they use cavities excavated by Northern Flicker woodpeckers! They also use nestboxes, as in the photo below.

Besides the Bufflehead, some other ducks that nest in cavities or nest boxes are: Hooded Merganser; Black-bellied Whistling Duck; Wood Duck; Common Goldeneye; and Common Merganser.

Crested Caracaras are distinctive birds of prey that live in parts of North, Central, and South America. Here are some cool facts about the Crested Caracara:

1) Crested Caracaras are fine at flying, but they can often be found walking around on the ground. Their long legs also make them strong runners.

2) While mostly quiet, the Crested Caracara has a distinctive social vocalization which is described as a rattle. The cackling, rattling sound is produced while the bird throws its head back in a move called the head-throwback display.

3) Caracaras are members of the falcon family.

4) Unlike many other falcon species, caracaras are not cavity nesters. They build stick nests high up in trees.

5) Like vultures, Crested Caracaras eat a lot of carrion.

6) The diet of a Crested Caracara may also include insects foraged through vegetation or eggs from ground-nesting birds.

7) Crested Caracaras look very distinctive, with dark bodies, a white neck, and a dark shaggy cap.

8) Baby Crested Caracaras have their dark cap from the time they hatch.

feeding time for the hungry baby caracara by belgianchocolate [Creative Commons]

9) The national bird of Mexico is the Crested Caracara (an honor sometimes shared with the Golden Eagle).

10) To intimidate nest intruders, Crested Caracaras may clack their beaks, or break off dry twigs to make a snapping sound. If you can't get enough of Crested Caracaras, you're in luck! This unique species is one of our newest Birdorable birds! Check out our fun collection of cute Crested Caracara apparel and gifts.

Black-throated Blue Warblers are small migratory songbirds. We've recently added this beauty to our family of cute Birdorable birds. Here are some interesting facts about the Black-throated Blue Warbler.

• Black-throated Blue Warblers are tiny birds, weighing in at just 9 or 10 grams.
• The four-letter alpha code that banders and birders use for the Black-throated Blue Warbler is BTBW.
• Based on bird banding records, BTBWs may live to be nine or ten years old in the wild.
• The plumage of the female Black-throated Blue Warbler differs greatly from the male. Early American ornithologists thought they were of a different species, naming the female the "Pine Swamp Warbler." John James Audubon even painted this bird as a separate species - today it is sometimes known as "Audubon's Extra Warbler."

Audubon's Pine Swamp Warbler detail

• BTBWs don't change their appearance as the seasons change, as some warbler species do. They are easy to recognize in the fall just as well as they are in the spring.
• BTBWs are migratory. Most individuals spend the winter in the Caribbean, especially in the Greater Antilles islands of Cuba, Jamaica, Puerto Rico, and Hispaniola (Dominican Republic & Haiti).

Be sure to check out our great collection of apparel and gifts featuring our cute cartoon Black-throated Blue Warbler.

A chimney that served as a roosting spot for Chimney Swifts for almost 50 years may reveal clues to the decline of the species.

Last month, headlines like "Clues to Species Decline Buried in Pile of Bird Excrement" and "Clues Found In Huge Pile Of Bird Poop" were good for a chuckle, but the data gathered by going through layers of swift guano has produced interesting information. By studying the droppings, scientists could determine what food items the swifts were eating. Prior to the widespread use of the pesticide DDT, the Chimney Swifts were dining primarily on beetles. DDT caused a huge decline in beetle populations, leading the swifts to hunt and eat different insects that didn't provide the same nutrition as the beetles. Chimney Swift populations have been declining, with a major contributing factor thought to be loss of habitat. This study implies that changes in diet may also have significant impact. You can read more about this study here: Historical pesticide applications coincided with an altered diet of aerially foraging insectivorous chimney swifts

It's here! May may be the most exciting month of the year for birders. May brings beautiful little winged jewels to the forests, parks and preserves in many parts of the United States.

With May also comes that unique birder affliction known as Warbler Neck. That's why May is Warbler Neck Awareness Month. Show solidarity with your birding brethren with original Warbler Neck Awareness Swag from Birdorable. The awareness ribbon for Warbler Neck is a cerulean blue feather ribbon.

It's May! Get birding! And remember -- be careful out there.