Not so much the cold weather but the amount of rain. Have you checked your box to make sure the nest was dry, drainage holes clear, opening positioned against the prevailing winds? Repair any damage or put up a new box. Other than that, its a sad loss you had no control over.

My sister lost 4 blues that would have fledged soon. Mom nested in a ceramic birdhouse sis made that did not have drainage holes. Needless to say, she has thrown the house out. Having lost nestlings so close to fledging is hard. All you can do now is make the second nesting the best you can provide for them.

Linda

I am sorry. I would think the rain could have caused this OR pesticides. I don't regularly monitor my boxes after the 12th or 13th day UNLESS I have concerns that there might be a problem. I do monitor (late) if we've had a blowing rain, etc.

Having meal worms (or not) would not have been a problem. Linda mentioned drainage and that's an idea, too. Does your box have good drainage? If we get a cold snap or strong winds and rain, I tape over my ventilation holes until the bad weather passes.

Again, I'm sorry but hopefully they'll come back and complete a successful nesting.

When there's a long peroid of rain the bugs hide making it harder for parents to find them. I've seen my blues feed earthworms durning long periods of rain. My understand is that earthworms aren't good for baby blues (I don't know why that is) Being it was the only food easily caught too many earthworms maybe the reason for your loss.

I would think that you would need to train your blues before the rainy weather to get used to eating mealworms, because sometimes it takes them quite awhile to find them. But you could start now training them and then give them some just every once in awhile. In between times you could offer them suet. Sorry about your loss. It's so hard. We all know!

Because we see robins feeding their young earthworms, we might assume bluebirds would too. Not really. But during spells of very wet weather, hunting for insects becomes much more difficult, and bluebirds might resort to earthworms. But bluebirds cannot digest them very well. From what I have read, it is because of the dirt castings in the worms' gut. Eating earthworms can cause severe diarrhea, which can result in dehydration and starvation, especially in the young birds. I have actually seen evidence of this, but I won't gross you out with the details.
Sometimes if I find certain insects while gardening, such as beetle grubs, I will add them to a glass dish in the mealworm feeder, and the bluebirds will enjoy those. Grasshoppers and crickets that I'm able to catch must of course be disabled first. The parents will love those, but only the older nestlings can handle those. Believe it or not, I've seen fledglings and adults eat small snakes, too, but I won't be catching those!
But again, no earthworms, thank you, please.
Bluebars

Dear Nif--
I had the same thing happen to me two years ago. A nest of baby blues were almost ready to fledge, then we had a nasty nor'easter and none of them survived. It was devastating! As far as I could tell, rainwater had blown in through the entry hole. At the time, I posted my story on this forum and I was told that in bad weather almost-fledgling bluebirds can be more vulnerable than younger babies -- maybe because they require more food, their parents give them earthworms or because they can't be physically shielded by a parent bird sitting on top of them?

Anyway, I followed advice given to me by the forum and made sure that the seams in my nest boxes were properly sealed and that all faced south to southwest in case we had another nor'easter. I was so spooked by the experience that when we had a bad storm the next year, I tied an extra piece of rigid plastic to the roof creating a massive overhang in front of the nest box entry hole. I don't know if it helped, but the nestlings were fine.

Thanks you for all your messages, it is so nice to have the advice of all those years of experience. :o)

It was really sad, my husband was actually more grieved than I was. :o(

I have put up a new box (Well, sort of, the blues kicked out a still empty TRES nest that was next to theirs no loss of eggs - only casualty were the feathers! And I made sure it is secure.

Now I have two TRES in the back yard near each other - weird year.

So I will print out your advice and follow it to the tee for next year. This will not happen again, if I can help it!!!!

Smiles

Nif

Nif I'm so sorry. I have all my boxes facing NE because that is away from prevailing winds and storms BUT the Nor Easter soaked my boxes and I had to do 2 complete and 3 partial nest changes. The 2 complete were both blues that had hatched and all survived. One set gets fed suet at my house and the other on my trail gets no supplemental food. Only the bottoms of the nests were really wet but I didn't want the hatchlings to be in a damp environment. The others were Tres nests with eggs only and I just changed the bottom third of the nests and left the tops intact. Hope things go better next time.
Cathy

So sorry to hear this Nif. Darn. The first nestlings I ever lost were to hypothermia.

See link below on preventing hypothermia.

Here is a link that might be useful: Preventing hypothermia and wet nests

Nif, I am so sorry to hear. Are you Jennifer that I have spoken to several times over the years? If so it's nice to see ya! If not, it's still nice to see ya! Good Luck in future BB nests!