Single parenthood at the Franklin hawk nest?

The three eggs hatched on a Monday.

But the celebration was short-lived. By Friday, events at the red-tailed hawk nest on a third-floor ledge of the Franklin Institute took a turn for the worse.

Avid hawk-watchers who have been monitoring the nest last saw the adult male that night at about 6 p.m.

"Since then, he has completely disappeared, and sadly, we have to start accepting that a serious mishap has befallen him - most likely some kind of injury or poison. As we well know, this nest is surrounded by highly trafficked city streets, but though several of us have prowled around for the past three days looking in all the areas where the hawks hang out, we have found no sign of him," wrote Plymouth Meeting resident Della Micah on her blog, which is all about the hawks.

Glenolden's Kay Meng, an amateur photographer who has become the birds' unofficial visual chronicler, put up a photo tribute here. It include 45 images. "These lovely images will remind us what a cool, remarkable hawk he was," Micah wrote.

Now, with Dad out of the picture, life becomes more tenuous for the three hatchlings. They have only one adult to keep the warm, hunt for them and feed them.

Micah writes that with the current warm weather, the young may be able to generate enough body heat while the female is out hunting. And, so far, she's been bringing back adequate food.

The blog has some of Meng's extraordinary photos of her feeding the fluffy little guys.

Meanwhile, the Franklin Institute staff is mulling what kind of aid the humans could give. A decision has been made to supply supplemental food -- putting dead rats or mice on nearby ledges, in the hopes that the female will spot them and accept them.  Yesterday, said spokeswoman Stefanie Santo, "the family did accept some food from us."

"It looked grim for a while," said Meng. But now she's hopeful the young will survive and fledge.

A posting just hours ago on the hawk's Facebook page may have the answer to what happened to the male:

"Hello, I have unfortunate news about what happened to Dad. On Saturday morning at about 6:30 AM I was driving east on I76 when I witnesse a Red Tail Hawk struck and killed buy a small truck in the left lane several car lengths ahead of me. The location was just west of the 30th street underpass, between the BFB split and the 30th oncoming ramp. Given the location and timing this was certainly Dad," wrote Mike Thierfelder.

"The bird came out from under the truck, skiddied accross the road ahead of me and ended on the right shoulder. I am possitive it was a red tail. He may still be there on the shoulder."

A volunteer went to the site to try to find the bird, in the hopes that they might be able to identify it, but it was gone.

So they may never know for sure.

"It is achingly sad to think that the tiercel is maybe gone. He was invincible as a hunter, and a superb provider for his family," Micah writes. "If he is indeed gone, the formel will look for a new mate for next year. The male hawk chooses the nest site, and initiates nest-building, and it is highly unlikely that he would choose to go the Franklin Institute nest."

Which means the hawks would be out of range of the webcam that has brought them worldwide celebrity, and we would not longer have this intimate view of the world of two hawks and their young.