Squirrels? Porcupines? You'll have to catch them red-handed to find out, which could be difficult (porcupines are nocturnal, so that'd mean staying up all night!). Very difficult to prevent, too, without caging the whole tree.

The tree will have plenty of small dormant buds which will grow to replace the lost buds, though it does mean that this year's growth will be rather less than expected. At least it won't be killed.

Resin

And if it is the flower buds, rather than the leaf buds/growth tips, being eaten, then you will get no, or fewer, flowers this spring. I don't know if they would work, so am offering it only as a suggestion - but one of the critter-ridder sprays, probably one that claims to deter groundhogs or rabbits, might work. I know red pepper/cayenne powder will mostly keep squirrels out of my bird feeders (I mix it with the seed), but didn't stop a raccoon from taking several feeders down from the hooks at night, and dragging them off into the bushes if they were hard to open (hanging the feeders from light ropes did the trick). If you are dealing with a large tree, the suggestion becomes impractical. It might be too late for this year, but you could make yourself a note and spray next year at this time or a bit earlier.

The other thing to remember is that the trees evolved with bud-eating "varmints", so it probably won't kill the tree unless the varmint (whatever it is) keeps it up over the entire spring and summer, for a couple of years. The tree won't get bigger, or will do so more slowly than it might otherwise, but it will probably live, as long as the varmint moves on soon.

Whatever the "varmint" is, it is probably attracted to the nutrient-rich buds, in the absence of other foods. You could always "give in to it", in a sense, and put out some other food that it can get to - either bird seed, suet or peanut butter come to mind. This would at least keep it from the chestnut buds. It would also, unfortunately, teach it to look to you for food, so it's a toss up.

Thanks for the replies.

Whatever ate the buds seems to have gotten its fill, as it hasn't eaten any more in the last few days, which is good. Only 1/3 of the buds remain, but I guess that's better than none.

Now, do I prune the very tips of the rough, chewed-off ends where the buds were eaten or should I just leave them to adjust naturally?

Casey