Science fiction paperback book about aliens who force people to stay in their homes and people meet in a virtual space called Oracle?

[wabranty]

I borrowed this book from the library back in the early 1980s. Birdlike aliens had forced people to stay quarantined in their homes. The protagonist is a person who is an expert in history? and he answers questions for other people through a shared virtual reality environment (Oracle?). He and his wife receive supplies through a matter transporter device. There is a scene where he meets with the aliens. I remember that the aliens fly around and chase any people who leave their homes.

 

[tegeus-Cromis]

But the main question is, when they're on Oracle, are they subjected to Oraclebombing?

 

[Boneman]

I hope someone finds this, because I have vague recollections of it... (keeps racking brain)

 

[Danny McG]

This is the oddly titled Ora:cle and the author is Kevin O'Donnell jr. Book published 1986.

Some details ...
It takes place in a fairly far-future where global warming has forced the entire (surviving) population of earth into living completely indoors in large apartment/office towers.
There are matter transporters that can only send non-living items (it kills living things). Some time after everyone moves into these towers the Earth is invaded by winged aliens called Dacs (short for pteradactyls).
The Dacs don't seem to care about taking over in any usual sense, they just keep us from developing space travel and hunt us for sport - but only if we go outside.

P.S @Bick This is one that's been read by me, relevant for your collective reading thread.. Collective Chronicles Reading Experience - Have We Read Everything?