Having indentured much of my life to seining distant raptors out of the ozone, or “dot watching,” as wife Linda calls it, I thought I’d treat readers to the sum of my knowledge (i.e., a crash course in the detection of high-flying raptors).
Many birders, steeped in the tradition of spotting birds with the naked eye and then studying their subject with binoculars, are ill-equipped to enter the hawk-watching arena, where most birds are spotted, even identified, before they are close enough to see without optics.
So, start with good optics, ones that will offer restful long-term viewing. Magnification, I find, is not a crucial determinant, although some hawk watchers swear by 10x. Me, I typically use 7x or 8x and find them easier on my eyes. Ergonomics are key. A glass you can hold steady without elevating your elbows reduces image-distorting shake. I find it useful to keep one elbow close to the body and rest the binocular on the tips of my fingers, thereby turning my non-focusing arm into a monopod. Then scan by turning from the waist.
Scanning is to finding hawks what scoping is to finding shorebirds. Early in the day, before thermal production puts raptors literally sky high, start left at a 90-degree angle to your body with the bottom of your field of view just touching the horizon and most of the field filled with sky. Turning from the waist, pan right until you have covered the entire lower portion of the sky in front of you. Having the horizon in view will keep you from panning so fast you blow right by a hawk before your eyes can latch on to it.
Following this initial scan, raise your binoculars one field and retrace your path, scanning the sky above your initial sweep. Three sweeps are generally enough to map the sky. If you find a hawk, note its trajectory and move your glass ahead one or two fields to see whether it is following another bird. Finding none, relocate your bellwether bird and search back along its path to pick up any trailers. Mark the location of that initial contact and concentrate your search efforts there. Conditions that attract one hawk (a strong thermal or opportune updraft) will draw another and create a flight path.
Later in the day, when thermals have sent hawks high aloft, it is productive to scan the base of clouds. Not only do clouds give your eyes something to focus on, but fair-weather cumulus clouds attract migrating hawks. They are the terminal stage of a thermal, those rising air bubbles hawks seek to gain easy lift. But any cloud base will do to silhouette hawks — cirrus clouds or even jet contrails.
Ants crawling on clouds
Once, while conducting a spring hawk count in northern New Jersey, I trained my binoculars on the base of a puff of cumulus and realized it had ants crawling all over the bottom of it. As I watched, a dash (—) passed through the ants. Translation: A kettle of migrating Broad-winged Hawks had coalesced below the cloud, and an adult Bald Eagle glided through. More often, it is the presence of large, dark soaring raptors that alert hawk watchers to the presence of smaller, paler raptors. It always pays to train your binoculars on vultures. They are your bellwether birds. Where they find lift, other raptors will, too.
A final trick I have used to some gain is to lie on my back and hold my hand over the sun. In this way, I’ve picked out raptors silhouetted in the sun’s bright halo without using binoculars. Yes, I wear exceptional sunglasses, and you should, too. A brimmed cap or visor is also helpful.
Some raptors migrate late. So even if the flight seems to have shut down by 5 p.m., you can still find Osprey, harriers, and Merlins moving until it’s almost too dark to see them. Conversely, harriers are often the first bird to be sighted by early arriving hawk watchers. Able to find lift where other raptors cannot, the doughty harrier can catch a thermal forming over warmer lakes and marshes on cold mornings. Paul Kerlinger and I once watched a kettle of 70 harriers form over Pond Creek one chilly November morning. The birds just kept pouring in from all directions to take the elevator aloft before setting off over Delaware Bay. Its 12 miles of open water is nothing to a harrier.