I was surprised to learn that the most accurate way to determine the sex of the bird is by blood samples.

How young they took the crows to mark them for identification

I didn't realize younger crows have blue eyes that turn brown as they age. Stunningly beautiful!

The use of the wing tags for identification from a distance makes perfect sense.  I was surprised that the tags were so durable and lasted so long, along with leg bands.  I didn't realize before how long a crow actually lives, so it makes sense that these identification tools would have to last as long, or nearly as long, too.

Longevity of crows

I was surprised to learn that the tags stay on the crows for so many years.

I found it interesting that the crows do not use their nests from one year to the next.  I also found it interesting that the birds had so many bands and tags on them.

The continuous monitoring of the baby crows.

I was surprised that the baby crows were be handled at such a young age.  I guess it makes sense to  identify them while they are still in the nest if they are going to be followed for their lifespan.

Crows living up to 19 years in the wild & the big colored tags put on them. I wonder if the tags affect them in some way. I imagine it would be easier for prey to notice them with their colored tags.

Monitoring the individuals into old age.  Fascinating

This is less about the methodology and more about the results:  the age of crows, especially here in New York.  I had heard that they lived beyond ten, but not that they lived well into their teens.  To be an older teen and still productive is pretty amazing as well.  The multiple banding makes sense, as many animals wear out/break tags in farming.  So it isn't surprising that each method has its limitations.

I loved learning about and seeing crows' nests.  The process and success of identifying crows was surprising and very clever.

Fascinating process!  Wonder if you ever have opportunities for interested members of the public to observe and/or assist?!

efforts to assess and monitor as individuals. did not realize that crows lived that long or that they are born w blue eyes

I was surprised at how in depth the crows are identified, marked and followed during their life cycle.  The longevity of crows was surprising given how tough living in the wild must be.

I found the tag half-life information really interesting! I knew birds were banded/tagged with multiple IDs, but I always wondered how long the tags lasted. Is there any evidence that the birds (or other animals) eat the tags after they fall off? The colorful plastic bands remind me of the Pacific Ocean garbage patch and the unfortunate number of birds who eat or feed their chicks the caps and other debris thinking it's fish.

This isn't an answer to the above question, but I wonder why crows don't reuse their nests in upstate New York? I've had the privilege of getting to know my backyard crows (in Red Deer Alberta, Canada) for the last 15 years. I feed them and they sometimes leave "sparkly treasures" for me :) I noticed one of the crows is getting white feathers on it's left wing like JG in the study so I assume it is age related.

Use of peanuts and tree climbing. The big tags also.

I had no idea that crows live so long!

That the birds don't try and get the tags off.

It is wonderful to know that you can get to know birds as individuals, from when they were in an egg until their death. I would guess that there is sadness when a bird that you have known all their life dies. And also, thank you for telling us where in trees we might see a crow's nest!

It was interesting that the teams need to look for new nest every year, as American Crows do not re-use their nests. The wing tags seemed large, and I wonder if there was any change to flying patterns as a result? I wonder, using radio and tag tech, what did you learn  bout how far a crow will leave its territory...do some travel hundreds of miles away and stay there?

It was interesting to learn why you used the wing tags as well as the leg bands.  I also found it interesting to learn that they do not return to the same nest and that they nest so high up at the top of the trees.  This year I hear them frequently in the woods behind one of the neighbors, and it makes me wonder if the nest is up in one of the white pines.  Thank you for the fascinating information.