What makes a bird a bird? Double crested cormorants are a type of bird that is well known to live in riparian zones along rivers, such as the Concord River. Birds make up the class of vertebrates called Aves. Their distinctive characteristics include their feathers, two wings, two legs, egg-laying ability, and beaks. Every bird species is unique in its adaptations and habitat range. Birds can be found in nearly every type of habitat. Their extraordinary adaptations help them to endure even some of the harshest of natural environmental conditions. Many bird species are especially attracted to riparian and wetland habitats such as the Concord River, because of their abundant and varied sources of food, water, and shelter. Lowell is home to a range of natural resources, the Concord River Greenway Park (Greenway) is one such resource offering birders an excellent place to observe many different bird species. A bird s-eye-view of the Greenway, is just that- a green way or path through the city. The Greenway is a refuge from the city for people and wildlife alike.
Flying overhead, looking down on the city, Lowell appears as a sea of gray buildings and roads with a beautiful green and winding Concord River corridor running north towards its confluence (joining) with the Merrimack River. Although much of the city presents great obstacles to wildlife, birds in general are adapted for flying to ideal locations along the Concord River in Lowell where they are able to find resources essential to their survival [being food, water and shelter].
Food, Water and Shelter With their remarkable camouflage and ability to fly to secluded spots,wild turkeys can live in the middle of a bustling city like Lowell. All living things need food, water, and various forms of shelter and other forms of protection.
Many bird species are attracted to the banks and waters of the Concord River for the abundant sources of food including: Fish Small mammals Mollusks Invertebrates Reptiles Plants Despite their camouflage, Northern brown snakes must be cautious because they are potential prey for many bird predators.
Low water levels in the Concord River allow seeds to collect along the river banks and expose invertebrates like aquatic insects crustaceans. Solitary sandpipers have long, slender beaks well adapted for excavating invertebrates from mud and crevices between rocks.
Water When a duck is not just a duck: Here we see two male mallard ducks (a male duck is also known as drake ). Because of their amazing adaptations and broad diet, mallards are one of the most commonly observed bird species in the world. Water is essential to the plants and animals of any ecosystem, including the birds living on and around the Concord River. This area is also called a riparian zone, because of the plants and animals that are often associated with rivers. The Greenway may be noted as a riparian zone, meaning that many of the plants and animals living here are associated with rivers and other wetlands.
Shelter Black-capped chickadees feed on the seeds of Japanese knotweed (See invasive Plants). Thick vegetation also provides excellent shelter from larger predators, such as redtail hawks flying overhead. Despite the hubbub of the city, birds have found ways to adapt to human settlements and find shelter and refuge among us. They are generally wary of human activity and prefer to keep out of our sight and range. A good birder knows very well to stay quiet always keep a pair of binoculars handy. Birding Tip: If you don t have binoculars handy, don t fret. If you curl your hands and put them to your eyes, as if your hands were binoculars, you will successfully block out distracting light and movement of random objects. This will help you to key in on the bird you are looking at with its color, shape, size, and more. Try it! Nests, Cavities, and Burrows A nest is a shelter specifically designed for protecting eggs and raising young. Many different types of animals, including birds build nests or use other natural surfaces to contain their eggs. Nests are generally used for breeding purposes only. Tree cavities, hollows, burrows, tree branches, bare ground, and crevices in rocks can serve
as nests, too. Birds sometimes use some of these same natural features during other times of the year when seeking shelter. The eggs of an English sparrow. Birds are very resourceful animals. They make nests from a variety of materials, such as sticks, grasses, leaves, mud, saliva, feces, feathers, mammal hair and even litter.
A bird nest built firmly in high up in a tall shrub offers protection from predators and rough weather. The unique hanging basket nest of a Baltimore oriole: This type of nest offers an advanced degree of protection, because it hangs that much further out of the way of tree climbing predators.
Tree cavities (holes in trees) can be excellent places to hide or nest for birds as well as other anmals. Woodpeckers, insects, and rot are responsible to making many of these tree cavities. Have you ever seen a broad-winged hawk near the Concord River? Chances are you would miss this particular raptor because of the color and pattern of its feathers blend in so well with the trees. This is called camouflage. For birds, especially small hawks, camouflage is very important because it protects them from predators and helps them to capture prey. Migration To birds like mergansers and goldeneyes, the Concord River is the deep south, a good place to spend the winter, away from the frozen lakes, rives, and ponds in Northern New England and Canada. So, don t miss out on birding along the Greenway during the winter months. January, February, and March are some of the best months to make an outing. Mergansers are diving ducks that have special beaks adapted for feeding on mollusks and fish and are often seen along the Greenway during winter months.
Other birds will fly south for the winter because of the cold New England weather and a decrease in food supplies. During spring months, these same birds will return as flowers bloom and insect populations become more abundant. The Baltimore oriole, for example, will come to the Greenway in search of nectar from flowers and will glean insects, which also feed on the flowers and sprouting leaves. Later in the season orioles thoroughly enjoy consuming fruits that are produced by plants and trees. Riparian Species The belted kingfisher is a unique looking predatory bird that can often be seen along the Concord River hunting fish. Kingfishers prefer to live in wetland habitats. River birch trees grow well along the banks of rivers, such as the Concord River, even during periods of high and low water levels. They are very flood resistant. Kingfishers will perch in river birch trees, while waiting to ambush prey and they will burrow deep into secluded riverbanks for nesting purposes. Like Water Off of a Duck s Back Birds feathers also help them in other ways, besides helping them to fly. Ducks, for example, have oil glands on their rear ends. They collect the oils with their beaks. When the birds preen their feathers, the oils are spread throughout their plumage, allowing them to stay dry, warm, and buoyant.
Mallard ducks are successful in part because, while preening, they cover their feathers in oils (their body s produce). Preening helps to keep birds clean and zip up breaks in their feathers, so they can fly well.
You can try preening feathers, too! Use your index finger and thumb, squeezing gently and pulling along the break in a feather and watch the tiny scales zip it back together. A bird s bones are cylindrical and many are nearly hollow making for a lightweight body, thus supporting the bird s ability to fly. Owls will generally not attempt to capture prey in water, because it is a risk that could lead to dire consequences. This great horned owl is a superior hunter with its binocular vision and loves to eat skunks. Great horned owls cannot smell skunks and are therefore one of their only predators. (Image: Courtesy of Mass Audubon Society-Drumlin Farm Wildlife Sanctuary.) Bird Vision While birds in general have a minimal sense of smell, they have excellent senses of vision and hearing. This allows them to hunt and evade predators with great success. Because their vision is such a dominant sense, their eyes are big, too big to wiggle them around like humans can. Birds compensate for this limitation by being adapted to turning their heads around most of the way (but never all the way around, not even owls can do that!).
Many birds, including songbirds and ducks have monocular vision, meaning their eyes are on the side of their heads. This allows for a very wide range of vision, and gives them the chance to quickly notice predators and flee from danger. As the saying goes, Eyes on the side, born to hide. This Bohemian waxwing has monocular vision. It is a bird born to hide within the safety of its flock and among the tree branches. Can you think of a mammal with monocular vision? (Think of another animal that often prey and born to hide.) Birds such as raptors have binocular vision. Raptors are bird of prey known for hunting by capturing prey with their sharp and powerful talons. Because their eyes are in the front of their head, they can identify prey at great distance and strike with precision. We say of such birds, Eyes on the front, born to hunt. Can you think of a mammal with binocular vision? (Think of another animal that is a predator and born to hunt.)
These red-tail hawks use their binocular vision to hunt perching song birds (passerine) and other animals unsuspecting of their stealth pursuit. Song bird and birds of prey are well matched, as song birds are masters of hiding and evading predators, while birds of prey are masters of hunting. Who will come out on top is a matter of skill, experience, and chance.
Here s trick question: Is this great blue heron born to hide or born to hunt? Great blue herons are known for their slow-moving, patient hunting tactics, which allow them to ambush and capture prey in shallow water. They are also known for their large size. Their size, as well as monocular vision helps herons to protect themselves from the pursuit of predators and detect subtle movement of prey. While monocular vision may imply that the heron is prey, its spear-like beak shape implies that it is also a predator. The great blue heron is born to hide and hunt. Many other animals also exhibit features of both predator and prey.
Activity - Scavenger Hunt: Explore the Concord River Greenway Here s a fun way to be a successful birder: Take an adventure the Concord River Greenway and explore the different habitats where birds are found. Make a scavenger hunt out of it! Directions: See if you can find all fifteen of the following and check them off as you find them. 1. Find a duck. 2. Find two bird nests. 3. Find three trees that produce food for birds. 4. Find three different bird species with monocular vision. 5. Find one bird species with binocular vision. 6. Find a spot on the Concord River where a bird can catch a fish. 7. Find a squirrel drey (Hint- It looks like a big bird nest, made by a squirrel). 8. Find three places that a bird can seek shelter. 9. Find two invertebrates (animals with no backbone) that a bird would eat. 10. Find two seeds that a bird would eat. 11. Find a small mammal that a raptor (bird of prey) would hunt. 12. Find a bird that migrates. 13. Find a place where a bird might safely bathe. 14. Find a bird singing a song to its friends and family. Can you whistle that song? 15. Find a bird perching on a tree branch.
Activity - Like Water Off a Duck s Back Experiment: Certain birds, such as ducks, have oil glands on their rears. As these birds preen their feathers the oils are spread throughout their plumage allowing them to stay dry, warm, and buoyant. Wax and oil from a bird s oil gland have similar properties. Water cannot be dissolved in either wax or oil. To test this, take a piece of wax paper and a piece of regular computer paper and drop a small amount of water on each piece. What happens? You will find that water soaks into the regular computer paper. Meanwhile, the water on the wax paper will remain as a drop and not soak into it. Water will not soak into oily feathers and the duck will have an easier time staying afloat.