Many baby birds are raised on caterpillars and larvae even if their adult form has a different diet. So it's entirely possible.

Absolutely! Some kind of unidentified species builds tiny, webby cocoons under our porch roof, and I see small birds swoop under and snag those critters all the time. It’s harder to spot the dining on and inside of roses, but I’ve caught a few birds grabbing something from Buff Beauty and Penelope and then flying away. Today a crow snuck up and snagged a potato chip at my daughter’s class picnic. :-) Carol

Seems entirely possible! I have a lot of sparrows nesting around the eaves of my house, and watching both the male and female going out get food and bring it back to the nest is amazing. I've seen them land on roses, poke around, and go back to the nest. And you're getting good bang for the buck, since I've always noticed the worst sawfly larva damage on roses grown close to a wall.

The larvae require adults to lay the eggs. The adults are flying insects (saw flies) so the sparrows could well be eating enough adults to prevent eggs and larvae. And, yes, it's possible there is some larvae harvesting going on, also. Sounds like a definite win to me!

We have way more house sparrows this Spring than we usually do, hmmm.. No idea why, but it sure is fun to watch them with their babies.

Jackie