Extra-terrestrials perhaps?

While clearing a section of the garden which has become somewhat overgrown, I just now came upon this clutch of four eggs, a discovery which I hasten to communicate to our members. They do not lie in any nest, simply upon the bare earth. What species of creature could have laid them there I wonder? Not a chicken, because - at an inch and a quarter - they are slightly smaller than hen's eggs and rather less oval. Perhaps a flightless native turkey, or some lizard-thing (I don't think snakes lay eggs do they?), or a small emu, or a Tasmanian tiger, or even a human being (do ladies lay eggs does any one know?) And surely being mid-autumn in this hemisphere it is not the season for eggs? Had they however rested there for six months would not some snake have found and consumed them? One of life's many mysteries.

P.S. They are definitely not mushrooms because I gave one of them a poke.