Why are baby bluebirds dying in Saratoga nesting boxes?

DEAR JOAN >> Years ago I bought a bluebird box, and since the violet-green swallows also wanted the space, I built three more and placed one about 50 feet from the first and the other two on the other side of the house.

Each year, we have bluebirds nest in one and swallows in the other, but in the past three years the baby bluebirds haven’t survived.

One year it seemed clear that the parents had been killed, perhaps by a hawk, as I found a pile of adult feathers below the box. But the past two years, I’ve only found the dead chicks in the nest.

Last month I removed a nest with four (dead) feathered chicks. Within days, two bluebirds built a new nest but left it with one naked chick inside an otherwise pristine nest, unmolested.

The swallows have been generally successful, but now I just found three dead feathered chicks in one of the boxes on the other side of the house. Am I doing something wrong? — Bob Burns, Saratoga

DEAR BOB >> We humans have a lot to answer for when it comes to wildlife survival, but in this case, I think you are blameless.

Sadly, many birds either don’t make it out of the nest alive, or are killed shortly after. There are a number of reasons.

At Our Garden, the Contra Costa Master Gardener’s and this newspaper’s demonstration garden in Walnut Creek, we have six Western bluebird nesting boxes, and over the years, we’ve had some unhappy endings. One nest was abandoned leaving five unhatched eggs, one nest had four babies that died, and this year, we had two birds hatch from four eggs, but both birds died.

In many cases, the death of one or more of the parents is to blame. The bluebird parents work together to care for the offspring, and if one is killed, the nest often is abandoned because it can be too much for the surviving parent to handle. It sounds cold, but often a surviving bird will turn its back on a nest or nestlings in order to find a new mate and start again.

Such is nature.

DEAR JOAN >> I have some small trays filled with water for birds to drink and bathe.

Recently, about 1 p.m., I noticed a hummingbird in one of the trays. Initially I thought it was dead as it was lying on its side and not moving. I picked it up and it moved slightly. I then dried it and placed it on a chair in the sun to warm up.

I decided to try to feed it as it appeared to have no energy. I placed my finger in sugar solution and rubbed it over its beak. The hummingbird started to drink the solution, and I continued for approximately an hour.

The bird appeared to improve, so I left it on the chair in the sun and monitored it from the kitchen window. After a while, it flew away. An interesting experience with nature. — Al Bruzzone, Richmond

DEAR AL >> The bird might have been stunned by flying into a window or another bird and somehow ended up in the bath. Hummingbirds also go into torpors — sleeps so deep they sometimes are mistaken for death. The bird might have chosen a dangerous place — the rim of the birdbath — for its nap and just toppled in.

I appreciate your efforts to save it.