“I think I see a hawk in the tree at 2 0’clock!”
“No; that’s a Raptor-Wannabe!”
Four of us piled into the Refuge van for the weekly Raptor Survey. Jac, one of the Nature Store staff, joined us for the first time. Between four pairs of eyes and varying levels of experience in locating and ID’ing our intended targets, we all learned something new or refreshed memories. The foursome also made for entertaining jokes, especially when the van wouldn’t start while out on the Refuge loop.
Informally lumped into the popular category, ‘raptors’, not all birds of prey are technically raptors. Eagles, vultures, hawks, and falcons share similar structures and functions. They all have powerful feet (raptorial) with sharped curved talons for catching and holding their prey. They also have strong hooked beaks for tearing their catch into pieces. Other ‘birds of prey’ that are not considered raptors are owls and osprey. Although they also have powerful feet and toes, they are arranged differently; hence they are classified differently. Our Raptor Surveys do not include the two latter species (the osprey is very rare here and owls are typically not active during daylight).
Raptors are commonly subclassified into informal taxonomical groups: the New World vultures, eagles, hawks, and falcons. Most all falcons are of the same genus (Falco sp.) , whereas most of the hawks in North America are of two genus: Accipiter and Buteo sp.
Identifying birds in the field is very similar to ID’ing plants: start with the obvious and the basics. Then dive into the details. The first field cues are size, flight pattern, and shape. With plants, it would be size, shape and growth habit (plants can’t fly ;).
Size: Birds of prey are generally larger than songbirds, although there are exceptions. The American Kestrel, a member of the falcon family, is the smallest with 10 1/2″ length and a 23″ wingspan. Not much bigger than a meadowlark. But like all falcons, a kestrel’s flight style and shape are similar to other birds of prey because of their food source. Yet, because of their body size, they fly differently compared to larger hawks and eagles.
At the other end of the spectrum, eagles are relatively easier to ID because of their large size and there are so few species. Hawks are the biggest challenge. Regardless, judging size in the field can be difficult and unreliable, especially at a distance. Flight styles and shape are field traits to consider next.
Flight: Typically, the smaller raptors fly closer to the ground. Marsh hawks (also known as Northern Harriers) tend to swoop close and parallel the ground, especially over shallow riparian areas, with wings upraised. They hunt for birds, frogs, rodents, and reptiles. Because of the small size and V-shaped wings, they are truly acrobats, turning on a mushroom.
Flight in birds is a function of their size and wing structure. The smaller raptors are quick and flap their wings more in flight than the larger birds. Eagles and the large hawks are more gliders than wing-flappers. Because of their large body size and weight, flapping their wings is very energetically expensive. Their wing beats are typically more deliberate and slow. They also use prevailing wind currents and thermals to take flight and glide. You will often see eagles and large hawks circling on thermal winds.
Shape: The overall shape and proportion of a perched bird or one in flight may reveal much information. Our favorite cue for a perched red-tailed hawk is its football shape. Kestrels are relatively easy to spot. Despite their diminutive size, the shape of the wings, squat head, and curved beak often reveal their identity.
Raptors in flight are a perfect opportunity to observe their tail length, shape and color, as well as their wing shape. Head size and neck length of perched raptors are another field trait that can differentiate them.
Occasionally a non-raptor plays the Trickster and fools us for a few moments. Several of the larger falcons and mid-sized hawks are nearly the same size and shape as the Common Raven. One of us might spot a dark form perching in a tree in the distance and call attention to it. Up go the binoculars and we all realize that dark perching bird is none other than a black raven: a Raptor-Wannabe! Such is what we call the ravens when doing our raptor surveys. (Ravens are not as easily confused as a raptor when in flight; their proportions and flight style are vastly different)
Our raptor counts can significantly vary each week, and from day to day. Our last survey revealed six Northern Harriers, which are common on the Refuge, and five kestrels. Today we spotted only three harriers, but eight kestrels! Only one of the colorful males was spotted, but with a brown mouse in its talons. The other seven were females, which typically hunt solo in the open fields. We were presented with three females hunting together in one field today!! It was like a finely choreographed ballet.
We reported to the others that this morning must have been a Kestrel Chic Day.
Our final count for just 1/2 of the sampling area this morning was as follows:
- Red-tailed hawks: 14 non-sexed adults (1 was a dark morph, 1 a rufus-morph) + 3 juveniles = 17 total
- American kestrel: 7 females, 1 male = 8 total adults
- Northern harrier: 3 non-sexed = 3 total adults
- Bald eagles: 1 non-sexed adult, 2 juveniles = 3 total
- Cooper’s hawk: 1 juvenile
- Merlin: 1 non-sexed adult
- Ferruginous hawk: 1 juvenile
- Sharp-shined hawk: 1 non-sexed adult
Because it was a warm day, and energized by the excitement of today’s raptor survey, I went for a walkabout on the Lagoon Trail. The wide and open trail wanders between two riparian canals on the side of the Refuge Auto Tour route, and across from the expansive marsh where ducks dabble and dive.
The two-mile plus walk was quiet and lovely, with tall grasses on one side and mowed native grasses on the other. I heard two hawks flying over the Chihuahuan desert brush land on one side. And heard the occasional quacks of mallards on the other side. Two scattered V-lines of snow geese flew overheard and I could hear the whoosh of their wings with their constant high-pitched honks.
Glancing down frequently in the gravel under my feet, mammal tracks showed big heavy mule deer, racoons in the dried mud, and one other string of human boots. A large deposit of fresh coyote scat revealed a partially digested diet of juniper berries, and even a small juniper sprig. In one line of big feline scat, I found a small white femur and other tiny tidbits of white broken bone encased in short light gray fur. Another tiny pile of scat further on suggested a young bobcat. Also discovered were two pieces of dried hide with long orange and beige fur! My guess was coyote or possibly red fox. Regardless which species, it was definitely from a wild canid.
Watching the raptors, spotting the tracks and scat, they all told stories of some of the wildlife that call this Refuge ‘Home’. I am perfectly happy sharing their Home with them. I couldn’t ask for anything more.