Stephane’s blog for June 2

Summer arrived without warning!


We left you in the midst of a big push by migrants, flocking through Cabot Head and into our nets. It feels like a long time ago now given that Summer decided to arrive early and largely unannounced. Late-May suddenly felt like mid-July!

The few days following May 25 were still filled with lots of birds: in the sky, in the woods, and in the nets (with totals of up to 45 birds banded in a given day). There were interesting birds detected: a Green Heron was seen flying across Wingfield Basin on May 27 (and again on June 1), a rarely seen bird here at Cabot Head; a Clay-coloured Sparrow was seen a few times during these same days; on May 28, we captured the first Gray-cheeked Thrush of the season; that day, we were also in awe of a big ‘kettle’ of 45 Red-shouldered Hawks, a sight I have never before witnessed here at Cabot Head! (a ‘kettle’ is hawk watch jargon for a large flock of raptors soaring together on a thermal); on May 29, a very strong South wind precluded us opening our nets, but census and observations went ahead nonetheless, which led to the discovery of FOY Black-billed Cuckoo.

After that day, capture numbers took a dramatic nose-dive: it seems that we are now catching the local birds, which are busy establishing their breeding territories, courting mates, and getting ready for a summer of love, being at their final destination after an exhausting migration. Indeed, as is typical at this time of year, very few ‘true’ migrants are now being seen. These birds are continuing their journey past Cabot Head as their breeding grounds lay north of the Bruce Peninsula, and include species like Wilson’s Warbler and Gray-cheeked Thrush.

As the warm weather settled over the peninsula, we started to enjoy our dinners outside. It was then that we experienced a great, yet quite unexpected, migration spectacle. On the evening of May 25, we heard, and then, saw five Common Nighthawks, FOY of course, and of note given that this species is now considered to be at risk, unfortunately. The next evening, we decided to be more thorough in our watching being outside from 6 to 9pm, and we tallied a total of 27 Common Nighthawks, with groups of up to six or seven passing above us at times. On May 27, only 10 Nighthawks were detected, which meant we were certainly not ready for what happened the following evening. On May 28, with Al Woodhouse, a long-term BPBO friend helping with the count, our tally climbed to a total of 70 Common Nighthawks flying high above the station. At times we could see groups of 12 or 14 birds, heading out over the bay. All of them called at some point, which allowed us to find them in the deep blue of a cloudless sky, and signaled their individual presence as we tried very hard not to double-count them. Later in the evening, their distinct calls ceased and the few nighthawks we still could observe had now initiated feeding behaviour. Some birds seemed to drift back from the bay and were not counted. The following evening, May 29, only 13 Nighthawks were detected. While on May 30, the wind had shifted to the Northwest, was blowing strongly in the evening, and no nighthawks were detected at all. Afterwards, we were not able to do an extensive nighthawk watch but have still spent some time in front of the station every evening. Alas, to no avail. As I write these lines on June 2, while dusk is gathering shadows over Cabot Head, and the evening was once again spent entirely outside from 6 to 8pm not a single ‘peep’ of nighthawks was heard. Is the migration over? Did we happen to witness a unique movement due to special conditions? Is late-May the peak time for Common Nighthawks to migrate up the Bruce Peninsula?

I am already thinking of next Spring and planning on spending most, if not all, evenings of late-May and early-June outside, listening and watching for these acrobatic dancers of the night sky.