Connecting you with nature
The red-shouldered hawk is one of the most beautiful (see the photos) and “talkative” hawks in the United States. If you’ve been fortunate to have one come across your path you might just fall in love. My first encounter with a red-shouldered hawk was seeing one, then a pair, perched in a tall tree in my backyard during a cold day at the height of winter about 5 years ago. Although I live in the big metropolitan city of Washington, DC, we have a lot of large tree canopy (urban forest) and we’re adjacent to Rock Creek National Park. The habitat is fairly good for red-shouldered hawks. It was the beauty of these birds, I could see through binoculars, that inspired me to learn more about raptors and how to photograph them. So, this past week when I came across a red-shouldered hawk nest just a few miles from my home, now over two years into my photography business, well, it was heaven-on-earth for me. In this post, I’m excited to share my first images of the red-shouldered hawk parents, their three hatchlings, and information about this species including some of the risks it faces.
Red-shouldered hawks are raptors, or birds of prey. Eagles and owls are raptors too, and this obviously means that there are different categories or types of raptors, each with their own behaviors, colors, sounds, and lifestyles. The red-shouldered hawk is in the “buteo” class of raptors. Experts differ in their precise descriptions of the size and characteristics of red-shouldered hawks, and tend to give ranges on height, weight, and wingspan. That’s reasonable; there are variations. In general, red-shouldered hawks may be anywhere from 15” to 24” long; weigh 1 to 2 pounds; and have a wingspan of 38” to 42”. Like some other raptor species, the female is larger than the male and there is no color difference between the sexes. Red-shouldered hawks get their name from the reddish-brown feathers on the upper wings. These feathers give the appearance of having red shoulders, although this part of the wing is actually the hawk’s wrist. Red-shouldered hawks live on the East and West Coast of North America. The eastern population lives from southern Canada to Florida and eastern Mexico and west to the Great Plains. Part of the eastern population is migratory. In the west, the species lives from Oregon to Baja California. The western population is nonmigratory. There is a difference in color between red-shouldered hawks in Florida and those farther north, which are darker in color. See the image directly below of a lighter colored Florida red-shouldered hawk and compare to the coloring of the adult pair from Washington, DC, that follows.
Red-shouldered hawks are forest raptors. They tend to live in forested areas with an open subcanopy and a nearby water source. Like other raptors, red-shouldered hawks are strictly carnivores. They’re diurnal raptors meaning they hunt during the day; they’re adapted for daytime hunting. They feed on many types of prey including amphibians, reptiles, birds, and small mammals including voles, chipmunks, mice, and possibly rabbits and squirrels depending upon their size. An image in this post shows one of the red-shouldered parents with a captured vole. Crayfish serve as an important food source, particularly in the southeastern US. In much of eastern North America, chipmunks and voles are the main prey. Red-shouldered hawks are chiefly perch-hunters, but may sometimes hunt while in flight.
Raptors have long been admired for their exceptional vision, which is a key element in helping them to locate and track prey. There are a few features of the raptor eye that contribute to its remarkable vision. First, like many other birds, raptor eyes are very large in relation to the size of their skull and their body mass. Second, even though raptors can’t move their eyes around like us humans, they have extra bones in their neck that allow them to move their whole head around. As many of us know, some raptors, like owls, can rotate their heads as much as 270 degrees! Hawks can rotate their heads almost all the way around as well. Third, the forward placement of raptor eyes gives them good binocular vision, and this facilitates very accurate judgment of distance. This is an excellent adaptation if you’re a perch hunter going after small, fast prey. Last, perhaps the most remarkable refinement to raptor vision is the ability to see in the ultraviolet (UV) light range. For raptors, who prey on rodents like voles and mice, this ability gives them a distinctive edge when hunting. Rodents, like many other species, use scent as a communication mechanism. For example, to mark territories, for mating, etc. So, in these species, long scent trails become obvious signs and pointers to where the animal has been. Scent marks of small rodents become visible when the markings absorb part of the UV radiation present in sunlight, and then reemit the absorbed energy as visible light. This is also called the process of fluorescence. Research has shown scent marks left by voles (who urinate almost continuously), are also detectable by raptors (kestrels) from reflected UV light. This ability, to perceive reflected UV, is particularly useful in the spring before the scent marks are covered by vegetation. For raptors hunting in open grassy areas this means they can rapidly scan large areas in a short period, and perceive rodents by simply following the ultraviolet trails that point to their movements and possible whereabouts. Put simply, just remember that raptors, including red-shouldered hawks can see the “pee trail” of animals they’re hunting.
Red-shouldered hawks become sexually mature at 1 or 2 years. Red-shouldered hawks, like other hawks, are monogamous and mate for life. However, if one of the pair dies, the surviving hawk may seek out another mate. Mating occurs between April and July. Red-shouldered hawks are particularly vocal prior to incubation, and they call repeatedly while engaged in courtship flights. The pair builds a nest of sticks, which may include moss, leaves, and bark. Nests are typically built at a crook of the main trunk in deciduous trees, more than halfway up the tree but within the canopy. The female lays three or four spotty lavender or brown-colored eggs. Females nest once per year, but may lay a second “clutch” of eggs if the first is destroyed. Incubation takes between 28 and 33 days. The first chick (“eyas” is the technical term for a nestling hawk) hatches up to a week before the final one. The female has the primary responsibility for incubating the eggs, while the male hunts, but sometimes the male cares for the eggs and the nestlings. Adults most frequently bring back mammals to feed the nestlings. Young fledge the nest when they’re between 35 and 45 days old and will try to catch their own prey, mainly insects. However, the young hawks continue to depend on their parents until they’re 17 to 19 weeks old, after which they may start to catch vertebrates. Young hawks may remain near the nest until the following mating season. Only half of red-shouldered hawk chicks survive the first year and few live to 10 years. The nesting success rate is 30%, plus red-shouldered hawks face many predators and risks at all stages of life. For those that survive their first year, red-shouldered hawks can live to be 15-19 years old in the wild, with one report of a 26-year-old hawk!
Threats to raptors come primarily from humans. While all animals are subject to natural threats such as disease and predation, raptors suffer far greater harm from human causes, including the loss of native habitat and habitat degradation largely due to human development and mounting population; intentional and unintentional killing (e.g., vehicle collisions) and poisoning (e.g., pesticides, lead); electrocution; and climate change, to name a few. Red-shouldered hawks, like other raptor and non-raptor species have important protections under various state and federal laws including the Migratory Bird Treaty Act. It’s unlawful to kill, capture, collect, possess, harass, buy, sell, trade, ship, import, or export any migratory bird, including their feathers, eggs, and all other parts. Habitat loss and degradation is the biggest risk that raptors like red-shouldered hawks face. It’s one of the reasons I believe that Land Trusts, which work to conserve land, can be a perfect partner in wildlife protection. I plan to write more on that in the near future.
A short while ago I wrote a post on lead poisoning in bald eagles. Red-shouldered hawks can face the same risk. Another distressing poisoning risk that red-shouldered hawks and other raptors face is from traditional rat poison (rodenticides). Many rodenticides stop normal blood clotting; these are called anticoagulants. Anticoagulants work by blocking an enzyme that controls blood clotting. If an animal (rat, mouse, etc…) is exposed to enough anticoagulant (rat poison/rodenticide), uncontrolled internal bleeding and death can result. Rodenticides have the same effect when eaten by any mammal, including a cat or dog. They can also affect birds. Anticoagulant and other rat poison products designed to kill rodents are also killing birds of prey, pet dogs and cats, and many species of wildlife, including several endangered species. Secondary anticoagulant poisoning of nontarget animals is well documented in a wide range of animals including owls, buzzards, coyotes, feral cats, mountain lions, otters, bald eagles, and more. Secondary poisoning occurs when a predatory animal consumes a poisoned animal, and ingests the poisons secondarily. Anticoagulant rodenticides are the most common method used for rodent control worldwide and they are frequently used in both residential and commercial areas, as well as in parks, cemeteries, and golf courses. Advice from the National Pesticide Information Center is helpful:
“When you are deciding whether or not to use a pesticide, balance the potential benefit against the potential costs, including environmental impacts. Sometimes using a pesticide, even according to its label, may cause harm. When that's the case, it is up to the user to weigh the costs and benefits, and if necessary, choose not to use the product.
If you use a pesticide, always be sure you read and follow all label instructions exactly. It will reduce the risk, but it won't necessarily prevent accidents. Read the environmental hazards part of the label carefully. Could use of this product harm bees or bats, or is it very toxic to fish? If so, and if fish or bees could be exposed, you might consider finding another product. Try to find the least toxic product that will do the job. It may be possible to take care of your pest problem using integrated pest management, which may mean using fewer pesticides, or possibly none at all.
You know your application area best. If you know certain spots are important places for special plants or wildlife, try to prevent contamination of those sites, especially at critical times of the year. You may also contact your state wildlife agency or the US Fish and Wildlife Service for more information. There are many federal and state laws protecting migratory birds, animals, and rare plants, but the most important protections come from ordinary people taking steps to avoid accidental harm.
To reduce risks of secondary poisoning for pets and wildlife, search for, collect, and dispose of poisoned rodents. Use gloves when disposing of dead rodents to avoid contact and secure trashcan lids to minimize pet or wildlife access to poisoned rodents.”
I hope to be able to update this post or add new posts as the red-shouldered hawk nestlings grow and fledge. This brings me to one of the most crucial points of this post – use your judgement and don’t unsettle or frighten this nesting hawk pair for the sake of photographs or the desire to simply get a peek. There’s already a lot of disturbances at this location. When I first came upon the nest site, I was stunned at how easy it was to see from the walking bridge I was on. This location is a popular, high-density, and well-traveled part of Washington, DC; not a location off the beaten path. Many people walk, bike and run across this bridge (often with leashed dogs), and there’s a lot of street traffic and noise. The habitat the hawks chose has many perfect features including high trees, open subcanopy and a beautiful stream, but there are literally people, apartments/condos, and noise all around, nearly all the time, and within easy sight of the hawks. So, yes, these birds may be somewhat acclimated to city life. Still, it’s crucial that anyone observing or photographing the nest use good judgement concerning the welfare of the hawks and their young. The highest priority here is a successful parenting outcome for this red-shouldered hawk pair, and no harm done by humans. If you stop to visit or photograph the nest site, use your judgement and common sense. Pay close attention to whether the birds are changing their behavior or exhibiting signs of stress due to your presence, or equipment. If so, back off. And even if this family of hawks tolerates some noise and a few humans, doesn’t mean they’ll tolerate a crowd or their tolerance will remain static.
Sources and further reading:
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