You certainly don’t see every single bird that visits your yard, so how do you get a rough headcount? Or how do you authoritatively tell a friend there were xxx birds in your yard? Experts disagree on details, but they’re in the same ballpark.
Count the birds you see in your yard in a typical ten second span (count those at your feeders, flying nearby and those just watching). Multiply that number by 5 or 6 (that’s where they disagree) for a very approximate number of birds who look to your yard for support.
cold facts about shivering Birds
shiver in cold weather, just like we do. Every bird in
the world does it to keep warm. Shivering keeps the core body temperature where
it needs to be (106-109 degrees for birds). That could mean a difference of 100
degrees from the outside temp to the inside of a bird.