Blue Jay Fledglings: How do you tell which is male?

For the past 3 days we’ve been caring for 3 beautiful blue jay fledglings (following all the recommendations) which fell out of their nest and with exception of one of them, which took first true flight today (sooo exciting!!! :smiley: ) the remainder 2 (nearly 1/2 the size of the one that flew to parents), are still in our care… btw, getting stronger and more daring (brief attempts at flying) each day! Anyway, one of the smaller birds has a much darker beak than the other two and just wondering if it’s male and the other 2 are female, or vice versa.

another btw, we get them outside (2-3 times a day) to allow their parent blue jays to feed them and interact with them, which they do regularly… at night and first thing in a.m., we hand feed the babies “baby bird formula” and they love it! We didn’t want to leave them out because there are 4 stray cats in the area and clearly all 3 fledglings needed more protection than their parents could provide… unless we wanted to allow nature to take its course (the strongest one would survive, 2 smaller ones wouldn’t and one seemed half dead when we picked it up)

As far as I am aware, there is no difference in plumage or bill color between male and female Blue Jays. While I don’t have a reference handy to confirm, offhand I would guess that males would be slightly larger than females. However, in the case of your birds, the size differences could easily be due to differences in laying times of the eggs (although most small birds don’t start incubation until the clutch is complete, so that all of the young are nearly the same stage of development), or more likely differences in the amount of food given each nestling. (The strongest young will beg loudest, get the most food, and end up being larger than its nest mates.)