No. not neccessarily. Male cockatiels usually are more vocal than females so start with that. If you still can not determine the sex. Look to see if he/she has lots of yellow around the face. If there is alot of yellow they are usually male. Then there the tail thing. Usually alot of the feathers will have the stripes but not all. If you still dont know, i suggest you take it to a vet and have it sexed.
FEMALE
You cannot. A female cockatiel needs a male cockatiel to mate with her before she will produce fertile eggs. And incidentally, birds do not "fall pregnant".
Yes. Your female cockatiel may lay an egg however without a male it will not be fertilised and therefore a dud.
Yes, they can learn.
A male finch can't really live with a female cockatiel as you should not mix straight-beaked and hooked-beak birds.
Yes, cockatiels love almonds. They have calcium and protein. If you have a female cockatiel feed her these when she is laying eggs.
the female parakets have lighter feathers and the males have dark feathers
Yes, that's how you get more cockatiels.
Maybe. Cockatiels have personalities and chemistry just like humans. My male used to be a jerk to my female, but now they have a baby and constantly preen each other.
male peacocks spread their feathers to attract the female peacocks!
Female cats in general, regardless of size, are called queens or she-cats. A pregnant female cat is called a molly.
This question makes no sense. A Heath is a small shrub.