I agree with Lisa,I don't think one bad day would do them in,Are the parents going to the box?This may be their first nesting ever,sometimes Sometimes it takes a couple of nestings with a young pair before they get it right.If you really want to try to provide food for them,I would take a shallow paper cup and tack it to the top of the box,and put some mealworms or wax worms in it,That way they can't miss them,But I would only do this for a few days,you don't want to attract other birds to the nest box.I do not recommend you bring the babies in the house,For one it is illegal,two,I doubt they would survive.And three,maybe the parents do have things under control.Most nestlings will hunker down during a nest check giving the appearance of a sleeping or weak bird.Just keep a eye on the parents,look for them to be carrying fetal sacks from the nest,If you see that then you know they are being fed.

Angie, Thanks so much! I'll tell you what I did in case anyone else ever needs to check the welfare of older nestlings. After my initial post, I went back out to look at the box to come up with some kind of strategy. When I saw a shiny, green fly near the hole, I knew I had to do something and fast! I got a deep bucket, a shallow dishpan, a wash rag, and two towels. I quietly approached the house from behind and plugged the hole with the wash rag. I then removed the entire house from the pole. I put the house down in the bucket and covered it with one of the towels. I set the dish pan right next to the bucket and covered it with the other towel. I pulled back the towel on the bucket just enough so that I could get my arm down to the box and also put my face down to the edge so I could see what I was doing. I tried not to leave any other openings and hoped that if they came flying or hopping out of the box, they'd land on the floor of the bucket or would hit my arm and face. I slowly opened the door (front opening box), and found three nestlings cowering inside. The smell was AWFUL, but at that point I couldn't see any actual signs of anything dead in there. I removed the nestlings one-by-one, examined them, and put them in the covered dish pan. They all seemed strong, were fully feathered, had stubby tails, and no longer had any sheathing on their feathers. All of their bellies were extremely messy from being down in the nasty mess of a nest, but other than that they looked good. I could hear them hopping and cheeping in the dishpan as I worked. I could see the remains of one nestling in the nest. The other one has either fledged or decomposed to the point that it wasn't recognizable. All five seemed healthy last Sunday morning, but it's been hot here so I guess it didn't take long for them to decompose to that point. I pulled out the old nest and replaced it with fresh grass that I pulled from the yard. I then reached my hand in the dish pan, under the towel, and picked up and replaced each nestling to the nest box, which was still down in the bucket. During this process, one did jump out of the house but landed on the floor of the bucket. Again, I tried to keep the bucket mostly covered with a towel so that they couldn't escape into the yard. Once I replaced all three, I closed the box and plugged the hole with the rag. I put the house back on the pole and waited five minutes or so before slowly and quietly removing the rag. I then moved off and watched to make sure none of them came out of the box. They stayed put, and within 10 minutes their dad was feeding them again. I know the box will still have some residual smell and that worries me. The pole is baffled, but I believe that a determined coon can get past that. I'm hoping that won't happen and that they'll fledge very soon. Once they leave, I will thoroughly wash the box and let it dry before replacing it. I'm hoping the male will find another mate and try again.

I would like to update my case. The HOSP made one more attempt (when the wounded BB baby was still alive, but seemed could not compete for food), but that time I noticed that BB parents behaved strange and hesitated to enter the house, though they did not sound very concerned. Just in case I approached the house and stuck my finger in, as soon as I puled it out, the HOSP male flew out and I even touched him, BB parents chased him away. If I knew it before I could catch him. I checked the BB babies and they were fine but scared. I was sure that day the HOSP would not return, The next morning, 2 days later after the first HOSP attack, I found the wounded BB dead and the BB female tried to carry him out. I made her leave the house, took out and disposed the dead BB (smell was already bad). I decided to exploit the smartness of the HOSP against him. As I mentioned he leaned that the spooker was not dangerous, and fishing line was also useless against him. I opened the front wall and left it open to serve as a perch site. Instead I attached two-entry patch and stuck it with a scotch tape. I was certain that the HOSP would be too smart to ignore the sudden transformation of the BB house. Besides the house started looking more scary, like having two big eyes. The other thing I pursued with this transformation is to have emergency exit or entrance, since the HOSP would not be able to block the both holes at the same time. With the 2 holes there was more light inside and I could check the nestlings without opening the door. At first the BB parents were confused, but shortly they figured out their babies were still inside and doing well. As the result I have not seen the HOSP around anymore, the BB parents became more defensive and the three BB babies have fledged yesterday. Now I need an advice or opinion: a) I take the BB house down until I significantly reduce HOSP population. Actually the HOSP infestation was not too bad first, but then numerous young HOSPs fledged from the neighbors house and the area became heavily infested. That house is like the HOSP farm, and at the same time HOSPs would almost never seat on my roof. b) I keep the BB house with the transformed front wall, c) I restore the house to its original shape, where I can set up a trap as needed. Thanks. This post was edited by stal14 on Wed, Jul 2, 14 at 11:24

It's a baby cardinal! And it just finally left the artificial ficus while it's parents called to it from a nearby tree! It's little "mohawk" is in, and the colors are that of a baby cardinal and not a cowbird. It just was very reluctant to leave the nest. Yesterday, it began to crawl out further onto the branches of the ficus, chip-chipping and a parent would answer back. The parents have spent so much time with this particular fledgling...I have to wonder about the safety of the other two. They're still out there. The male comes flying out from under our window shrubs when blackbirds are in the front yard and issues his "alert." What a relief...but now, that little chipmunk from next door! I started tossing seed balls into their own shrubbery to keep the chipmunk away and am using live mealworms and safflower. Might have to take down the suet, since the cowheads/blackbirds seem to like it far too much and come into territory where the fledglings are hiding. I read they will fly within 20 days. It's now 14 days since I first noticed the birds were hatched. They could have hatched before I saw them. So when should they begin to fly? I know the parents do stay with them and "train" them.. But that chipmunk! Thank you all for responding to my "cardinal adventure." What a lovely song they sing. : ) ...And I just watched the little guy hop off with both parents very near. I don't hear them now. Just so they're all safe!