Raptors Extinct and Extant

While working at World Bird Sanctuary’s Stone Zoo bird show in Boston, I have learned to make three major distinctions indicative of raptors: excellent eyesight, strong grasping feet and a sharp, curved beak.

Steven Spielberg’s Jurassic Park has made Velociraptors famous, but what do these prehistoric “raptors” have in common with modern raptors? They certainly don’t have a curved sharp beak or grasping feet.

It turns out Velociraptors and other theropod dinosaurs with raptor in their name such as Oviraptor or Eoraptor aren’t even closely related.  However they are united under the Maniraptoran clade, which means “seizing hands,” a nice parallel to extant (meaning living today) raptors’ seizing feet. They are defined as being more closely related to birds than other dinosaurs.

Dromaeosaurid (photo: wikipedia by Tom Parker)

Dromaeosaurs, or “running lizards,” are a group of Maniraptors containing Velociraptors and other “true” prehistoric raptors defined by their large grasping hands, a stiffened tail and one large, slashing claw on each foot. Modern birds of the Aves class are the sister group to Dromaeosaurs. You can compare an artists’ rendition of an extinct  raptor to our extant raptor, Diablo the Tawny eagle below.

Today we have many different raptors within Aves, which belong to different groups as well. The orders Accipitriformes, Strigiformes and Falconiformes are an example of convergent evolution and each produced unique raptor species.

Accipitriformes is the most diverse raptor order consisting of many different families of eagles, hawks, harriers, kites, osprey, the secretary bird and Old World vultures.  New World vultures of the Americas are not related to Old World vultures of Africa, Europe and Asia.  They have merely evolved to fulfill similar ecological niches.

Osiris, the Egyptian Vulture is an Old World Vulture (photo: Gay Schroer)

Baton Rouge, a King Vulture, is a New World Vulture (photo: Gay Schroer)

New World vulture phylogenic placement has proven to be difficult with DNA evidence supporting their inclusion in both the bird orders of Accipitriformes and Ciconiiformes or storks. Old World vultures are true raptors, while New World vultures lack the strong grasping feet of raptors. You can make this comparison between Osiris the Egyptian vulture (Old World) and Baton Rouge the King vulture (New World) at our Stone Zoo bird show.

Riley, a Barn Owl (photo: Aurora Potts)

Strigiformes consist of two main families of owls; barn owls and typical owls. Owls are mostly nocturnal and are therefore more sound sensitive than other raptors. Barn owls belong to the family Tytonidae.  Their face is heart-shaped and their legs are longer than that of Strigidae owls. Typical owls belong to the more varied family, Strigidae. You can see these distinctions on Riley the American Barn owl and Reese the Great Horned owl at our Stone Zoo bird show.

Reese, a Great Horned Owl (photo: Aurora Potts)

Naturally, Falconiformes are falcons, which are more closely related to songbirds and parrots than they are to any other raptor (believe it or not). Falcons are the speedy and agile birds of prey that use their tomial tooth at the end of their beak to break their prey’s spine. You can see the notch that is the tomial tooth on this Peregrine falcon on exhibit at Stone Zoo.

A Peregrine Falcon on exhibit at Stone Zoo

Even though extinct and extant raptors are hardly related, you can see all these fascinating predators possess many adaptations.   Their unique characteristics allow for a wide variety of species to share the generally speedy seizing and grasping raptorial name in prehistoric times and up to modern day.

Submitted by Aurora Potts, Naturalist/Trainer for World Bird Sanctuary’s Stone Zoo Show

Bill Size and Shape

One of my favorite things to do, during migration season is to identify birds.  Many aspects of bird watching combine to make this the world’s number one hobby; the hunt through the binoculars for that wind-blown leaf you thought was a bird;  the sudden realization that you’re facing the wrong direction in a valley; following a song for an entire afternoon just to get a glimpse of that fellow who sings his heart out. 

When I do finally see that special bird, I have to take quick mental notes on size, color, foot type (if I see a bird feeding), bill type, and behaviors.  Although behavior is a really big part of identification, I enjoy using bill type as a guide for those really tough ones.  This is especially true when you consider that many species depend mostly on a specific food for survival.  Whether it feeds on seeds, insects, nectar, or other animals, its bill will be specially adapted for feeding.

Members of the parrot family have beaks that are designed for gripping and cracking seeds and nuts.  (photo: Leigh French)

Seedeaters need to have a bill that is strong enough to crack through the thick hard hulls to get to the meaty fruit inside.  Their bills are often thick and arrow shaped having hard ridges to aide in grip, like a wrench.  Parrots are a great example of this.  Their bills are very thick and their upper mandible has serrations on its underside, out near the tip, so that they can grip nuts and crack them.  Also, cardinals have a thick, strong bill for smaller seeds.

Shorebirds are a wonderful example of diversity within a habitat.  Gulls and terns have bills adapted for fishing.  They dive into the water from the air or from floating on the water. 

Roseate Spoonbills have a bill shaped for shoveling around in the lake bottom debris for their food. (photo: Gay Schroer)

Some Ducks and wading birds have a specialized bill for shoveling around in the water for invertebrates. 

This Scarlet Ibis has a very specialized beak for probing for food in soft mud and under plants (photo: Gay Schroer)

Birds like the sandpipers, oystercatchers, godwits, turnstones, and plovers have bills that are shaped for finding invertebrates that have tunneled into the sand or mud.  Their bill is sort of shaped like the prey for which they forage. 

Herons and egrets use their bill as a spear.

This Great Blue Heron uses his bill as a spear and then swallows the fish whole (photo: Gay Schroer

…whereas this Yellow-crowned Night Heron snatches his preferred diet of crayfish with his long pointed bill

…and then turns it, pinchers side out, and crushes it with the powerful upper portion of his bill before swallowing it

Moving away from the shore, there are other smaller birds that flit about after tiny gnats and flies.  These birds have small bills and are a bit more difficult to identify because they are usually small and fast.  These are typically gnatcatchers and flycatchers. 

Prothonotary Warblers have small thin bills for catching insects and snails which they pry out of their hiding places

Ruby-crowned Kinglets are such tiny little birds and they are the most difficult for me to see clearly.  That’s when I listen to any calls or songs they may be making.  Woodpeckers have a bill that is like a chisel.  They bang away at trees looking for insects crawling under the bark and inside the wood.

Finally, I think crows and ravens are a good transition into birds of prey.  They are very adept and intelligent.  They hammer and poke and tear and pull their food.

Meat eaters are probably more diverse because they may feed on certain animals based on their habitat.  Owls, hawks, and eagles have bills that are great for tearing meat.

The Eurasian Eagle Owl has a beak that is supremely well adapted for tearing meat (photo: Gay Schroer)

So, when you are having trouble narrowing down that bird species, perhaps you can get a good look at the bill to figure out a bit about it.

The next time you visit the World Bird Sanctuary, pay particular attention to the different beak shapes that you will see on our display birds and the birds that visit our bird feeders.  Try to guess what each bird’s preferred food would be.

Submitted by W. Leigh French, World Bird Sanctuary Naturalist

Raptors in the Wetlands

In the “World of Warcraft” gaming crowd, you will find maps on the Internet of Raptor Ridge Wetlands in the Eastern Kingdom. 

It is the place in that virtual world that is considered a ‘contested territory,’ full of various marshes full of different types of fauna and wildlife.  The rocky ridge overlooks the watery flats below.  The raptors are attracted to the cliffs, where they can take off and soar over the marshes, looking down for easy prey.  The marshes (wetlands) below make for a whole world full of watery surprises of life, diverse and thriving, including the humans who wander into it and carry on their activities for living there.

A Peregrine Falcon feeding on a kill (photo: the wikipedia files)

It often works that way in the real life worlds of wetlands, waterfowl, and raptors -- especially the Golden Eagles, Bald Eagles, and Great Horned Owls.  In doing limited research for this blog, I found a great source of information from the “Ducks Unlimited” website, written by Scott Yaich, PhD:  “While it would be easy to assume that fewer raptors would mean more ducks, no studies have indicated that these birds take enough waterfowl to significantly depress their populations. Waterfowl and raptors have shared the same habitats for hundreds of thousands of years, and in healthy ecosystems both groups of birds thrive in "the balance of nature." Like most predators, raptors tend to take the small, the sick and the weak. For example, a study of crippled mallards in Wisconsin found that most of the birds were killed by predators.  Raptors, including Red-tailed Hawks, Northern Harriers, and Great Horned Owls accounted for about half of the predation.”

Now, let’s add human activity to this biological diversity.  Wetlands have long been identified by the Army Corp of Engineers and other wildlife managers as very necessary corridors for migrating waterfowl.  Also, various hunting organizations who lobby Washington have fed plenty of research dollars into restoring, maintaining, and even adding habitats for the waterfowl.  An added benefit is that most wetlands, by the physics of water running through roots, dirt, and rocks, are considered ‘nature’s filtration system’ and are often constructed to help clean up sources of pollution while also supporting a resurgence of wildlife in the neighborhoods where they are placed, even around subdivisions. 

All of these protected areas, even the seasonal marshes that may dry up during the hot summers, add to the rich diversity of life’s food chain from the ‘bottom feeders’ of mice and insects, on up to the ducks and waterfowl of open water marshes, and to the ‘top feeders’ of raptors.  It stands to reason that a well-designed, well-managed wetlands project can add great biodiversity to any construction project.  The best part is more release sites for rehabilitated raptors  into areas where we civilized humans may not be so accustomed to seeing soaring raptors anymore.

In upcoming blogs, the multi-tiered diversity of wetlands and raptors will be explored more.  It offers another great insight into how human activity and development projects can still be ‘inter-connected’ to our conservation practices, especially for the benefit of raptors.  Our human activities – our daily lives – can add to the diversity of the ecosystem in a healthy way.

Submitted by Paula Arbuthnot, World Bird Sanctuary Part-time Employee

Thinking in Haiku

Sometimes inspiration hits and you go with it. 

Lately, I’ve been thinking in haiku. A haiku is a poem with a pattern of five syllables in the 1^st and 3^rd lines, and seven syllables in the middle line. Here is an example  based on the birds. Enjoy!

“Raptor”

Raptor; Bird of Prey

What makes you so? A hooked beak,

Sharp talons, strong feet

Eyes are important

We spot food from miles away

They help us see prey.

What do you eat? Meat!

Wait…. Then catch it with my feet.

Mammals, birds, reptiles

Submitted by Christina Lavallee, World Bird Sanctuary Naturalist