BLOOMINGTON - John Tobias is looking forward to Memorial Day Weekend. That's when the director of the Miller Park Zoo expects to learn whether one or both of the two eagle eggs laid at the facility in recent days will hatch. | Archive video | Photos | Related stories

Incubation period for Bald eagles is 32 to 34 days, according to experts. Counting the days since Beauty, the zoo's female eagle, laid her first eggs in 13 years puts the hatch near the end of this month, Tobias said.

Bird experts Given Harper at Illinois Wesleyan University and Angelo Capparella at Illinois State University, have said they hope the eggs are fertile, but there's no guarantee.

Signs are good, including the fact Beauty and her male partner in the enclosure, Mathata, appear to be taking turns incubating the eggs.

The zoo staff has taken precautions to reduce potential disturbances at the eagle enclosure. Routine mowing, which normally occurs every 10 days, has been suspended.

"That may become a very tall-grass exhibit soon," Tobias quipped.

To avoid other unnecessary intrusions, Tobias on the advice of the zoo's consulting veterinarian Matt Fraker earlier abandoned an idea to candle the eggs, a routine process that merely requires shining light through the shells to see if embryos are developing.

Harper said Thursday the outer appearance of the eggs does not indicate whether anything is alive inside.

The only time staff approach the eagle enclosure is for a once-a-day afternoon feedings. Each bird receives 1.5 to 2 pounds of fish daily. Both mature birds are eating well and appear healthy, Tobias said.

Still, Tobias and his staff are being kept busy with other eagle-related work. More visitors than usual are being drawn by publicity surrounding the rare event that began when a visiting wild eagle appeared at the zoo for four days earlier this month.

The eggs appeared a few days apart during its visit. Though it's hard to tell male and female eagles apart, Harper and Capparella both think the visitor was a male based on its behavior, which included roosting in a tree above the open-topped enclosure.

Neither Mathata or Beauty can fly due to injuries which landed them in captivity. If the eggs are fertile, no one can know if the father is Mathata or the visitor, or if the visitor's presence merely encouraged Beauty and Mathata to mate for the first time after so many years.

DNA testing of the chicks, if they hatch, can provide an answer.

Tobias said he is also fielding eagle questions wherever he goes.

"At the pharmacy, 'How are the eagles doing?'… At the doctor's, (the nurse) said, 'Your blood pressure is OK, but what about the eagles?'" Tobias said.