Brandon Holden Photography
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Spring Hawk Migration Through Lambton County
On April 1 st, 2007 I was finishing up a day of birding in the Sarnia Area, when I decided to visit the Bright’s Grove Sewage Lagoons. On previous visits, I had noticed a few hawks in the air, and after scanning the ducks in the cells, I noticed they were again flying through.
A handful of Red-tailed Hawks was enough for me to decide to hang around, and see if there was any sizeable migration passing through the area. Since I was on the lakeshore, I figured it was possible that a good migration of hawks passed through the area. Within a few minutes, under strong S/SW winds, I realized that a steady migration was passing overhead. I tried to keep a loose count in my head, but I soon lost track. Red-tails and Turkey Vultures were steadily passing through.
From when I started watching until the flight slowed ( 3:15pm to 6:15pm) I made a conservative estimate of 500+ birds. While the Vulture’s and Red-tails dominated the flight, I also recorded good spring numbers for Sharp-shinned Hawk, Cooper’s Hawk, Northern Harrier, American Kestrel, Merlin, Red-shouldered Hawk, Rough-legged Hawk, along with my first Osprey of the year.
After spending many happy hours hawk watching at Beamer C.A. in Grimsby, I was excited to think I would be able to do the same while staying in Sarnia. The next day, I had some spare time in the afternoon, so I returned for 4 hours and counted a respectable total of 186 birds in less ideal conditions than the day before.
High flying (migrant) Turkey Vulture
After two days of good observations, I decided to make an effort to do other counts (under good conditions) in order to see if large flights occurred with the other species. Unfortunately, most of early April brought some of the worst hawk weather I had seen in recent years, which prevented me from conducting a count.
It was now well into April, and Broad-winged Hawks were on birder’s minds around the great lakes. Hoping to see a flight myself, I snuck out for a few hours here and there and counts of 200-400 birds on a few different days kept me excited, however the big flight had yet to be recorded at any watch around the great lakes.
My day would come on April 24th, as I was leaving an exam at Lambton College, I stopped with some friends to reflect on how well we thought the exam went. Keeping an eye to the sky (as all hawk-watcher’s do), I noticed 5-7 Broad-wings flying high under a cloud. I pointed them out to a friend, and talked about some migration habits of the species. He quickly informed me however; that there were “more than 7, something like 15” So I looked up again.
15 grew to 20, 28, 38, 47? A large kettle had formed right over our heads, easily seen against a line of clouds. The weather forecast (of light NE winds) wasn’t the best for a hawk flight. I kept an eye up, another of kettle of 25 formed to the north within seconds. Another group of 30-40 overhead after the first group left. Thoughts of studying, and my previous completed exam quickly left my head. My friends continued to count the groups, quite surprised that this many hawks could fly overhead. In less than 5 minutes, our count was well over 100 birds. The next kettle however, which I counted at 128 birds, was enough for me to wish my friends the best of luck studying, because I was now going to spend the day counting hawks!
I ran back to my room, grabbed my scope, camera, pens and paper, and decided to set up on the soccer field behind the school. Kettle’s of Broad-wings poured overhead. About 50% of the groups were over 100 birds. As the NE winds picked up, the birds were pushed south. I followed the flight line until about 2pm, when the cloud-line dissipated, and I lost track of the flight. My end count of 5500+ birds was much higher than anything I had expected. Many hundreds or even thousands could have passed over before I started counting (around 10:30-11am) and many more could have continued to fly after 2pm.
So despite the fact I did very little studying for my exam the next day, it was still successful for me. I know had great proof that a large spring migration of hawks passed through the area, and were often concentrated enough to perform counts. Below are a few additional notes and observations about hawk watching in the area:
- the hawks fly west to east
- Sandhill Cranes were seen in low numbers on most good hawk days
- South winds concentrate birds along the lakeshore, however N winds can spread them out. (No escarpment to provide lift on N winds like Beamer C.A.)
Broad-winged Hawks over a telephone pole, during my large flight in Sarnia.
So where do the hawks come from? I think there are two reasons that the birds are concentrated through this area.
The first is Lake Huron. Birds that are trying to enter into Ontario may fly too far North in Michigan, and actually have to fly south (or due west) to get around the southern end of the Lake, to continue the journey north into Ontario breeding grounds. (see map below – Pink arrows)
The second reason birds might get concentrated here is a combination of Lake Erie and Lake St. Clair. Birds hitting the west end of Lake Erie might head north to Sarnia, around the west end of Lake St. Clair (instead of making a bend around the south and east part of Lake St. Clair). (see map below – Red arrows)
I often found myself watching on the laneway to the Bright’s Grove Sewage Lagoons, as I could also check the cells for other birds once the flight slowed. Other birders may find a better location for future dates, and hopefully many more will get the chance to enjoy some great hawk watching in Lambton County!
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