Monday, November 30, 2009

HawkCount...So Much More than Just Daily Totals

Chances are, if you are a hawkwatcher and spend time visiting watchsites during the spring and fall months, you are familiar with HMANA’s hawkwatching database, HawkCount (www.hawkcount.org).

Since I began hawkwatching in 1999, I have treasured HawkCount as a means of staying up-to-date on what’s happening in Maine, Texas, Illinois, Mexico...you name it. I begin by easily locating watchsites by state or by province from the drop down menu or by using the interactive map. Next, I simply click on an active watchsite and find hourly, daily, or seasonal totals by month or by year – and you’re there! Scroll down to read the summary reports and highlights, a world of raptor observations at your fingertips.
For years, this is solely what I used HawkCount for. But the fun doesn’t stop there...

Click on SITE PROFILE for each site and there you will find general site descriptions, topography notes, history of the site and directions. I find this section helpful when I’m planning a trip to a new site or curious about the length of the count season or just learning about the site’s history, like when it was established. Also included in the Site Profile section are photos of sites, maps, contact information and website links.
Interested in reading about specific protocol or articles highlighting a certain watchsite? Check out the Procedures/Protocols section.

Many of you may be very familiar with HawkCount and all its functions. However, I’ve realized through talking to hawkwatchers how many of them are not.

Aside from these site details, this page also displays big days and season records - my favorite feature. Just check the “Migratory Raptors Observed” table and you’ll see maximum daily and season counts and timing calendars that let you know the migration window for each species at each site. For me, it’s really helpful to get season highlights from certain hawk watches without having to dig through months of data. It’s a very useful tool for Site Coordinators who may be conducting simple analyses, writing final reports or just having fun playing with data.

As HMANA’s Monitoring Site Coordinator, part of my job is to keep HawkCount updated with new information. This means reaching out to Site Coordinators and working with them to fill in the gaps and encouraging people to follow HMANA’s guidelines and to enter data regularly so it can be viewed and enjoyed by everyone. We hope to have the majority of site profiles updated by the end of the year but we would love your help. If you’re a Site Coordinator and looking to update your info in any way, please contact me at tilden@hmana.org.




Wednesday, November 25, 2009

Reporting Short-eared Owl sightings

Bird Studies Canada, a HMANA partner, asks you to report any sightings of Short-eared Owls this winter. 2009 is the group’s seventh season of monitoring Short-eared Owls.

North American and European researchers are working together to learn more about this poorly-understood species, which appears to be declining across its global range and is classified as a species of Special Concern in Canada.

Bird Studies Canada has used satellite and radio telemetry to track large- and small-scale movements of Short-eared Owls in Canada for two seasons. With funding from TD Friends of the Environment and Ontario Ministry of Natural Resources Species at Risk Stewardship Program, BSC will continue the program this winter.

Birders are asked to report any sightings of Short-eared Owls this winter; including the date, location, time, number of owls seen and the type of habitat in which they were observed.
If you would like to report a sighting, or if you're interested in volunteering to monitor known roost sites across southern Ontario (or know of a site that hosts wintering Short-eared Owls), please contact Hazel Wheeler, 1-888-448-2473 ext.165, hwheeler@birdscanada.org.

Data from the study will help determine the seasonal habitats of the owl as well as identify important breeding and wintering sites. Updates on the group's satellite-tracked owls are at the Owl Tracker.

Friday, November 20, 2009

Sharpie-Cooper's Ratios



As someone who has been hawk watching for over 35 years, I’ve been fascinated by the changing fortunes of the Cooper’s Hawk. Following HMANA’s Hawk Migration Studies, Hawk Count, and RPI (Raptor Population Index), it is clear we’ve had a dramatic increase in Cooper’s Hawk over much of the continent during the past several decades.

When I started hawk watching in Massachusetts in the 1970s, one rarely saw a Cooper’s Hawk. The best time was in late September and early October, when you might hope to see one a day, maybe two, at selected watch sites. Most New England sites covered by experienced observers reported something like 35 to 40 Sharp-shinned Hawks for every Cooper’s. There was much discussion about identification difficulties, in part because people saw so few Cooper’s; they are so similar to Sharp-shinned Hawks; and there were no good field guides on hawk ID. There was considerable skepticism about some Cooper’s reports.

Looking on a broader geographic basis now, sharpie vs Cooper’s ratios remain very intriguing. For example, Lighthouse Point in Connecticut reported 9,080 sharpies in 398 hours in 1980, and only 84 Cooper’s, a ratio of 108:1. In 2009, in 544 hours of coverage so far, Lighthouse has reported 5,308 sharpies vs 1,221 Cooper’s: 4.3:1, a dramatic change.

Looking somewhat farther south down the coast, in 1980 Cape May in New Jersey reported 52,282 sharpies and 1,615 Coopers, 32.4:1. So far in 2009, in 784 hours of coverage Cape May reported 13,710 sharpies and 5,497 Cooper’s; 2.5:1 significantly lower than Lighthouse. (Both of these coastal sites report primarily birds of the year.)

Looking inland, Hawk Mountain in Pennsylvania reported 8,319 sharpshins, and 374 Cooper’s in 846 hours of coverage in 1980, or 22.2:1. In 2009, in 875 hours of coverage to date, Hawk Mountain has had 4,291 sharpies to 601 Cooper’s, or 7.1:1.



Going farther inland, and north, Holiday Beach in Ontario reported 12,460 sharpshins in 1980, vs 316 Cooper’s, a ratio of 39.4:1. In 2009 to date, in 582 hours of coverage Holiday Beach has had 9,699 sharpies and 938 Cooper’s; 10.3:1.

Intriguingly, out west where the data set does not go back as far, in 1991 in 707 hours of coverage the Goshute Mountain site in Nevada had 3,674 sharpshins and 2,726 Cooper’s: 1.3:1, far lower than any eastern sites. In 2008, the most recent data available, the Goshutes had 4,697 sharpies and 1,957 Cooper’s; 2:5 to 1, suggesting accipiter trends in the west might be quite different from those in the east.

Several things are abundantly clear. All four eastern sites are seeing far fewer sharpshins this year than they did 29 years ago. Second, they are seeing many more Cooper’s Hawks now. However, the magnitude of the changes in ratios varies, often somewhat dramatically, from site to site. What is going on? This comparing snapshots of accipiter migration in two different years (four, including the Goshutes) has clear limitations. Looking at moving averages can provide a better picture of what is going on. To look at RPI data for sharpies and Cooper’s from 17 sites across the continent, visit RPI.



Photos by Joseph Kennedy. Used with permission.

Monday, November 16, 2009

Migrating Red-tailed Hawks... or Not?



Many hawk watches are still looking for and seeing migrating Red-tailed Hawks. One of the things I especially like about late season migration in the northeast is that the late October/November light on migrating redtails shows them at their very best. Never are the colors richer, warmer, and more beautiful on a Red-tailed Hawk than when bathed in afternoon sunlight in early November.

However, in recent years I have been conscious of another growing movement of Red-tailed Hawks, at least in the greater metropolitan Boston area. More Red-tailed Hawks are breeding in heavily developed inner suburbs – and even the core city – than ever before, not just in the wealthier, greener suburbs. Breeding redtails now occupy virtually every major intersection on the major interstate highways in the region. In at least two intersections in my corner of inner suburbia, multiple breeding pairs occupy territories based on the four separate sets of conspicuous vapor lights, on which they frequently perch; that is, two or three different breeding pairs pair consistently perch on specific vapor lights at one cloverleaf.

I’ve also found that a number of these urban redtails – at least a number of adults – do not leave their breeding areas in the winter. Those birds whose most prominent perches are on vapor lights on major cloverleaves appear to occupy the same perches all year round. Locally nesting redtails who do not use the vapor lights generally do not appear to use their most prominent breeding perches regularly during the winter. They are seen intermittently during the winter, however, periodically checking out their nest sites. This seems particularly true for the adult females.

What happens to the juvenile offspring of these urban redtails? The assumption has been that they disperse and eventually migrate. I have not seen the one apparently still surviving young of my local redtail nest for months.

However, I have seen young of other breeding pairs in the area on the same perches – primarily on the interstates – on which I’ve seen them since they fledged months ago. Will they eventually depart for warmer climes? Or will they become part of the growing urban, settled redtail population?

Other redtails move into the area for the winter, some of whom appear to be western-type redtails. (One bander in southern New England says he has seen dramatic shifts in the wintering Red-tailed Hawk population over the past decade or so, seeing the first and growing numbers of western-type redtails.)

As indicated in the State of North America’s Birds of Prey, published by the Raptor Population Index (RPI), many hawk watches in the northeast have seen a decline in annual redtail numbers over the past four decades. Is this due to there being fewer redtails, or as in the case of the Sharp-shinned Hawk, are more Red-tailed Hawks migrating shorter distances, wintering farther north, or even wintering on their breeding grounds now than in the past? The Christmas Bird Count data for the U.S. from 1960-61 to 2008-09 shows a significant, consistent increase in the number of Red-tailed Hawks seen on CBCs. Are you seeing decreasing migrant redtails over the years, or increases in the number of year-round birds?

Wednesday, November 11, 2009

Peregrine Falcon Identification on North Carolina's Outer Banks

Working to improve our skills at identifying distant peregrine falcons on North Carolina’s outer banks, we were fortunate that raptors appearing at a great distance almost always ended up flying closer to us than 400 meters, sometimes directly overhead, and sometimes very close and below eye level. The narrowness of Ocracoke Island at our observation site could be thanked for this advantage. So we were able to verify our identification of distant birds once they were close enough to display plumage and other ID-clinching details. This was a treat compared to the work at our spring hawk watch where migrating raptors first seen at a distance frequently stay very distant.

Clark and Wheeler in Hawks of North America describe peregrine falcon flight as typified by “shallow but stiff and powerful wingbeats, similar to those of cormorants.” This was a marvelously helpful description for us, because cormorants were visible from our lookout almost continually. When there were no raptors to look at, we could concentrate on the sometimes hundreds of cormorants in the air at one time and imagine their wingbeats on a distant raptor that needed identification.

Clark and Wheeler’s description of peregrines in a glide, “glides with wings level or with wrists below body and wingtips up,” was also very helpful, especially because most of the distant peregrines we saw were head-on pencil lines. After about a dozen peregrines, we began to feel pretty confidant of our distant identifications.

The other feature that really struck us about the peregrines was how quickly they changed from very distant to very close birds, even when they were powering into a headwind. This in itself proved not only distinguishing but exciting. Probably the thrill of seeing a peregrine in the wild is closely related to what is often the quickness and fleetingness of the experience.

Now that we’ve returned inland from our coastal birding, where several times we saw more than 12 peregrines zip past us in 30 minutes, we’re looking forward to seeing next spring’s 12 inland peregrines spread out over two months. We’re also looking forward to the confidence we’ll have in our identifications, even if the peregrines never get very close.

Sunday, November 8, 2009

A site for watching coastal falcons

Data from the Kiptopeke raptor watch on HawkCount made it easy to determine the best dates for seeing falcons along the Outer Banks of North Carolina. The best window for peregrines was clearly late September and early October. We wanted to watch the falcons from Ocracoke Island, which is just south of Hatteras Island.

Ocracoke Island lies in a northeast to southwest orientation, is about 15 miles long and ranges in width from around one-quarter-of-a-mile to two or three miles. We had observed peregrines and merlins flying low and fast over the sound-side marsh, the surf line on the ocean, the beach and the dunes. Our observation site ideally would provide a good view of all these features of the island.

A parking area at one of the narrowest parts of the island provided access to some tall dunes that overlooked marsh, dunes and beach and was relatively clear of vegetation that might block our view. The site should offer good views for a number of years to come, but we’re not sure that we can make the commitment required to establish a formal raptor watch that would require hundreds of hours each spring. Well, we can dream!

Modest numbers of ospreys, harriers, cooper’s hawks and sharpies provided a nice contrast to the few kestrels, merlins and many peregrines migrating past the site. Migrating monarch butterflies, swallows and cormorants fleshed out the resident non-raptor activity, which included least, royal, caspian, common, sandwich and gull-billed terns; great black-backed, laughing, ring-billed and herring gulls; seaside sparrows and yellow-rumped warblers; sanderlings, red knots, ruddy turnstones, willets, black-bellied plovers, and one marbled godwit (that showed up every day for two weeks). If the avian activity slowed, small pods of dolphins showed up on a couple of days to keep us entertained.

Wednesday, November 4, 2009

Falcons on the Atlantic Coast

Coming from a spring hawk watch on the south shore of Lake Erie, we see very few peregrine falcons or merlins during our formal season, perhaps five to ten birds of each species in an average year. Although we do see fairly good numbers of migrating and local kestrels, in order to get our falcon fix we travel to the Atlantic coast during fall migration to see merlins and peregrines.

There are a number of excellent established fall hawk watches on the coast (check out HawkCount on the internet). We’re partial to Kiptopeke on the southernmost tip of Virginia’s eastern shore. But for the last couple of years, we’ve chosen to find our own observations points south of Kiptopeke.

Although we know migrating raptors in fall, especially falcons, travel down the line of barrier islands (the “outer banks”) south of Kiptopeke, currently there are no formal hawk watches operating and reporting regularly to HawkCount for hundreds of miles south of the Virginia border. So setting up south of Hatteras on Ocracoke Island in North Carolina allowed us to feel a little bit like pioneers. Also, barefoot and shorts and t-shirts in October was a nice contrast to the duofold long underwear, balaclavas and mittens we associate with our official hawk watching duties during Lake Erie’s spring.

Our coastal fall hawkwatching goals were educational and recreational. We wanted to improve our skills at identifying peregrines and merlins, and we hoped for the excitement of at least quick looks at some of North America’s most dramatic avian wildlife. The peregrines, at least, didn’t disappoint us this year.

During one two-hour period in early October we saw nearly 40 migrating peregrines. Flying into twenty-five mile-per-hour head winds, the peregrines came fast and low, skimming over the vegetation in the dry marsh, mostly below eye-level from our observation point in the dunes.

Sunday, November 1, 2009

Always check behind you!

Merlins are well known for their aerobatic shenanigans with other raptors during migration. And a lot of Merlin hits are taken by innocent watchsite owls (Bubo plastiptero) at lookouts across the continent. B.plastiptero also suffers antagonism from Sharp-shinned Hawks and occasionally, Cooper's Hawks.

During the autumn of 2009, however, observers at New Hampshire's Little RoundTop Migration Observatory were witness to the determined harassment of Bald Eagles by Cooper's Hawks. Passing Merlins seemed intent on zooming toward their migration goals, the occasionally mischievous Sharpie might dive-bomb a Broad-wing or Red-tail, but the Coops seemed particularly intent on needling other birds. We watched them go for Broadies, ravens, Red-tails, and even a Kestrel, but it was their pestering of Baldies that captured our attention. We would wonder, "How long is s/he going to keep that up?" And keep it up they would, sometimes all over the sky.

Always the target bird would seem undeterred and continue on its way with only the slightest discernable twitch of primaries. This sort of drama does present a problem for site leaders, because...

as everyone is watching the show, there's a chance that something really good is flying past behind them!