Tuesday, September 16, 2014

Hawk Ridge weekly count summary 7-16 September 2014

This has been another great week at Hawk Ridge, with lovely weather and loads of birds! Raptor numbers are slowly building, but I don't think we have hit peak migration yet. The cooler weather this week with lows in the 30s and 40s pushed some good numbers of Broad-wings into our airspace, with over 13,000 seen in the last week, including a nice flight of 5554 on September 15th. Many of the kettles were seen late in the day on the 15th so we were hoping this was the set-up flight for an even bigger flight on the 16th, but the clear blue skies were mostly empty of kettles and only 329 Broad-wings were found. The variety of raptors has been excellent, with all of the regular species except for Rough-leg being seen on the 16th, including several early Golden Eagles on the 15th and 16th, single Swainson's on the 12th and 16th, and as many as 9 Peregrines on the 16th. The 16th also saw an excellent flight of American Kestrels (photo below), including a morning count of 104 on the shore. Recent forecasts show another front coming on Saturday with westerly winds, so I am sure all those raptors are just waiting for hawk weekend to fly by!

Female American Kestrel flying a few feet over the hawk counting platform at Hawk Ridge. Thank you!

Non-raptor migration has been amazing this week, with record numbers of Blue Jays and thrushes. We have had a good movement of Canada Geese this week, including 2066 on September 9th, which is one of the higher counts from Hawk Ridge, but oddly enough no other species of geese have been seen. Where are the Cackling Geese? Sandhill Cranes and American White Pelicans have also been regulars in small flocks, including a good count of 112 cranes on September 11th. The Great Egret which was also seen on September 11th is an unusual sight for Duluth, and only the second I have seen from Hawk Ridge. No doubt this was probably the peak week for Blue Jay migration, including really good days of 4,102 on Sepetmber 9th and 4732 on September 11th, but then an amazing 9,490 flew by on September 15th, which is a new one-day record for Minnesota! For several hours in the morning, there was a nearly continuous river of Blue Jays following the same invisible path along the shore. What a sight! Over 27,000 Blue Jays have been seen this week alone.

Blue Jay in migration over Hawk Ridge
Another view of a Blue Jay in migration over Hawk Ridge
large flock of migrating Blue Jays
But despite this record flight of jays, the highlight of the week has to go to an even more amazing flight of thrushes. Although Swainson’s Thrushes are an abundant nocturnal migrant, when hundreds or perhaps even thousands can be heard, these shy and reclusive birds are seldom seen in any numbers during the day, and are not usually thought of as a species which typically engages in redirected migration after sunrise. Normally these nocturnal migrants put down before it gets light out and disperse into woodland habitat where they are only seen on the ground in very small numbers, so it seemed quite unusual to see a large morning flight of thrushes after sunrise on September  13th, including 74 Swainson’s and 4 Gray-cheeked (and 37 unidentified Catharus thrushes), which as far as I know is a record diurnal count for Swainson’s. Many were quite high above the trees, some were even in small groups, many were calling, and others were identified by taking their photo and zooming in to see the distinctive face pattern (today’s digital technology allows us to take a quick photo that shows us detail we could never see with binoculars as a bird quickly flies by).  Although it was tempting to think this was the peak of thrush migration, on September 15th an even larger flight occurred, although fewer individuals were identified to species in the morning flight (it takes a perfect combination of low flying birds and sunlight to be able to identify them). Before dawn beginning at 4 am, I heard hundreds of Swainson’s Thrushes and counted 40 Gray-cheeked Thrushes mixed into the continuous peeping of the Swainson’s. Then, just as the sun rose, thrushes began flying out in redirected diurnal “migration”, resulting in 46 Swainson’s, 6 Gray-cheeked, and 188 unidentified catharus thrushes being counted, certainly the largest such flight I have witnessed. Every year we document something new and amazing with our non-raptor counts, and this year the highlight has certainly been the morning flight of thrushes. I think Swainson's Thrushes are one of the most common migrants along the North Shore, but because they mostly migrate at night and are reclusive by day, most people do not realize how truly abundant they are (think about how many Swainson's Thrushes you see each fall in normal birding); in previous years I have heard fall-outs at dawn twilight with so many calls ringing through the air that the numbers were simply uncountable. Who knows, perhaps there is an even larger flight of thrushes to come yet this year! I included some of the photos I took of Swainson's Thrushes the last few days to give an idea of what they look like in flight overhead.

Swainson's Thrush flying overhead in morning sunlight, showing the buffy wing stripe
Another view of a Swainson's Thrush in flight showing the buffy spectacles which distinguish it from Gray-cheeked Thrush
Swainson's Thrush engaging in redirected migration well after sunrise
Another view of a Swainson's Thrush flying directly overhead, showing the wing stripe- in flight they resemble small stubby American Robins

rainbow in front of Hawk Ridge- we waited ten minutes for a bird to fly through this brightest of rainbows but we were not so lucky

Karl Bardon
Count Director
Hawk Ridge Bird Observatory

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