The "protection added" to the nest had become "a threat" to the security of the "nursery" that the birds had worked so hard to built. When security has been compromised, the birds feared for the safety of their young!

Often, it is better not to impose "human values or judgment" on animals.

But, my observations show that most birds are likely to rebuild another nest somewhere else and to lay new eggs and hatch them again -- if "food" supply, temperature and security are good. Because, this is what birds "must" do once a year.

Depending on what birds, little bits of "their" food in odd places for them everyday for about 3 weeks, could help.