Before you run out to an hunt wild bird eggs, you might want to check your local laws. Hunting songbird and game bird eggs is illegal in most of the United states. But if you are starving and stumble upon a bird’s nest, you can poach, fry or hard-boil them. When I was young, eating raw eggs was considered ok, now it is frowned upon and considered unsafe. I have eaten my share of raw eggs and would in an emergency.  But you have to make your own decisions.
In the past collecting wild bird eggs for food was common practice. The good news is that no wild bird eggs are considered poisonous. But you may want to examine them to see what their state of development is. You can do this by candling the eggs. This is simply shining a light though the eggs. This works with most types of eggs, there are a few that are not translucent and this will not work on. The name comes from the fact that in the old days they used candles. When you shine the light through them, you can tell if the embryo has started to develop. A fresh egg will be clear, as the embryo, starts to develop you will see a reddish brown area with blood vessels extending away from it.  If the whole egg appears to be dark, you have a whole chick inside it.
Now the fact that the embryo is developing does not prevent you from eating the contents. You just need to be very hungry or have a strong stomach. I recommend that if you are cracking several eggs that you first crack them in a separate bowl, so that if one is bad you do not contaminate the entire batch. The method of cooking that preserves the most calories is the hard-boil them.
In the United States the largest egg is the goose egg, they are about twice the size of a chicken egg. Goose nests are amongst the easiest to find. But the geese will fight and try to keep you from stealing their eggs. Geese lay their eggs in March or April depending on the weather. They take about a month to hatch.  Most wild game and song birds will lay their eggs in spring and early summer.
Take a bit of time and learn about the birds that live in your area and where to find their nests. If you only take a portion of the wild bird eggs, they will continue to breed and you will have a long-term source of eggs.
Howard
How about pigeon eggs? I think that pigeons are overlooked as a meat source. I don’t know how difficult they are to raise as my one effort was quickly destroyed by hungry raccoons.
Wild pigeons, especially city pigeons, can generally be expected to be full of disease and/or parasites. Raising “fresh” chicks from eggs taken from wild pigeons may work. But again, you are dealing with wild animals, not domesticated birds. And if you’re going through the effort to raise and maintain a coop of birds for eggs/meat, why aren’t you just raising chickens or another already domesticated bird in the first place?
On another note, there are breeds of domestic pigeons which are bred and kept for food (see squab).
Town, City forbids raising poultry
Goose eggs aren’t the best thing in the world to try to eat. Like the parents, the taste takes some acclimation to tolerate. Furthermore, scrambling is the only halfway satisfactory method of cooking; boiling creates a golf ball consistency and frying turns it into a hockey puck.
How about for cooking ingredient?
I foung goose eyes to be delicious. I cook them over easy. Fantastic! Disagree with hockey puck description. Absolutely no different than a domestic chicken eggs. I cannot eat chicken eggs (pheasant family) due to allergies. Goose eggs are Waterfowl (different family) and fabulous!