These types of die-offs are concerning, but probably more common than you'd think. People don't generally realize what a rough life birds, especially highly migratory species, have. A pair of song-birds (passerines) will likely hatch an average of ~4 babies each year, and yet the populations are generally stable or shrinking over time. Using rough math that would indicate that 2/3 of the birds that exist at the peak breeding season will not be alive the next year.

Weather-related events are pretty tough to predict and prevent. There are several things you can do that will have a direct effect on bird populations. I'm short on time, so I'll just list the two most impactful ones:

1. Keep your cat indoors. The low estimate for the number of birds killed in North America pet and feral cats is one billion birds a year. That doesn't include the many small mammal, reptile, and amphibian species which are the base of the food chain for larger species of birds.

2. Reduce your use of insecticides both directly and via store-bought foods. There's a lot of evidence that insect populations are experiencing a population collapse, likely due mostly to accumulated insecticides in the ecosystem.