It's crazy how fast these little guys grow! Only 4 days old, and they're filling up the nest waaaaay more than they were on Friday. They're starting to look a little more bird-like, too. :) I think their heads are starting to catch up with their eyes. I also noticed that the slits on their eyelids are forming. The slits are even able to open a little bit. I'm guessing that they must be able to see little glimmers of light when that happens. Their feathers are fluffing up more, especially on the tops of their heads. They still sleep a lot, all snuggled together. They are more than happy to wake up on a moment's notice when Papa or Mama Robin come along with food, though! I was even able to get one (very blurry) picture of one of the parents feeding them today. Hoping to get a better one eventually, but those silly deck boards don't make for easy picture taking. :)
A few things I've observed over the past 4 days: Papa Robin seems to bring most of the food. He brings big beakfulls of all kinds of juicy critters, and makes sure each one of the babies gets some of the bounty. Mama Robin usually just brings one critter at a time and feeds one baby at a time. For the first few days, I noticed that she would feed one of them, then sit down on top of them and fluff her feathers out--I think to warm them up. This seemed to be her main job. Now that they're bigger she isn't spending as much time on the nest (from what I can tell). I'm assuming she still snuggles up on them at nighttime, but I'm not sure. All of the babies seem to be growing at the same rate, so obviously the parents are good at figuring out whose turn it is to get extra calories when they need it. :)
I know I've said it before, but it is SO cool to get this up-close look at the growth and development of birds!!