While reviewing Robert Manning's short, though detailed video of the Lake Wanahoo Cuckoo, there were a few points in the video where red flags were raised.
1.) The bill, though dark looks swollen and straight, and not small or curved. Young Yellow-billed Cuckoos, depending on the individual can posses a dark bill for months.
2.) The white on the throat and underparts is very clean and pristine.. There is a good shot of the throat, and even adults should show a bit of buff in this region. I usually think of Black-billed being a bit more off-white. Though even with the darker overcast conditions, this bird appears quite pale.
3.) The tips of the retricies are very large, bright white, and prominent as pointed out by Michael Willison. Black-billed Cuckoos including adults should have more subdued smaller tail spots.
4.) The field mark I first noticed took place in the last few seconds of the video. Though blurry, rufous can be observed in the underwing when the bird takes flight. Black-billed Cuckoo should never show rufous in the underwing.
5.) Calls of Black-billed and Yellow-billed can sometimes sound very similar. A dry staccato-like call is a vocalization shared by both species.
Yellow-billed Cuckoo especially young birds can be a tough ID. I remember incidences similar to this on Illinois's IBET listserve regarding intense scrutiny and discussions involving fall photos of various cuckoos.
Just my two cents.
Justin RinkMidtown Omaha, Douglas Co., <NEspindalis79...>
At approximately 12:15 pm today, I heard a Black-billed Cuckoo right next to my car as I was scoping some Horned Grebes from my car on the bridge that is 1 mile north of Lake Wanahoo, the road that passes through the wetlands and sediment trap area. The call sounded very close to Sibly's 4th call down the list "call series...NY". I was really surprised and found it briefly and I got a short video of it. (I posted the video on my YouTube Channel, see the link below.) I had my camcorder ready to video tape the grebes to make sure they were horned. There were two juvenile grebes and one adult. The adult disappeared on me.
I got a very good look at the Cuckoo first, then I had trouble focusing my camcorder on it. It flew about 3 seconds later into a dense growth of young Willow Trees and other trees, about 20 yards east of the bridge. That dense growth of trees goes on for about 100 yards and is at least 50 yards wide.. There is a lot of water in the ditch just east of the bridge and I did not have high boots with me to try to relocate it. I walked up and down the road for about a half hour without seeing or hearing it again.
I posted a screen capture from the video in my NEBirds folder.