I got the goslings this morning and introduced them to their new mother. It did not go smoothly. She got up and hissed at them, but I palmed them and snuck them under her, and all was well. The goslings were happy and stopped whining, and mommy settled peacefully. Until they got out to eat and drink. Then the hissing started all over, and she has continued to hiss at them all day whenever they get up and move around.
They found their food and water, so they won't starve or go go thirsty. And she lets them snuggle under her wings after a good deal of hissing. I was afraid she'd bite them, but they don't say anything when she touches them with her bill, so I don't think she'll harm them. But nothing has changed in her behavior all day, and I don't know if I should let them stay with her during the night. Will they be safe?