"Hello Hans and Terry,
Wow, I'm jealous, I haven't seen a flight like that since I went to Veracruz, MX. The bird you circled is a broad-winged hawk. Broadwings come in two morphs a light morph which is the majority of the population and a much rarer dark morph. At Veracruz, less than 0.1% of the broadwings are the dark morph. You can see in the picture that the size and shape of the dark morph is the same as the light morph broadwings around. The characteristics of the dark morph are a dark belly and underwing coverts.
Let me know if you have any questions,
David R. Barber
Hawk Mountain Sanctuary
Today a huge Hawk migration. I think I did see the biggest in my 20 years of living in Panama. The sky was full in Bocas del Toro along the cost (Panama)...wow!
Mostly broad winged Hawks, Swainson's Hawks and Mississippi Kite, Turkey Vultures. Also loads of groups of Swallows, what I did see for sure... northern rough winged Swallows and Bank Swallows and a few southern rough winged Swallows...but also Swallows that I could not see very well for a proper ID
Greetings from Terry