The Patient Cat by Laura E. Richards.
https://americanliterature.com/author/laura-e-richards/short-story/the-patient-cat.

The Patient Cat was published in Ms. Richards' collection of morality tales and poems, The Pig Brother and Other Fables and Stories (1881).

Is it always wise to wait? Timing is everything in this feline morality tale.

When the spotted cat first found the nest, there was nothing in it, for it was only just finished.
So she said, “I will wait!” for she was a patient cat, and the summer was before her.
She waited a week, and then she climbed up again to the top of the tree, and peeped into the nest.
There lay two lovely blue eggs, smooth and shining.

The spotted cat said, “Eggs may be good, but young birds are better. I will wait.”
So she waited; and while she was waiting, she caught mice and rats, and washed herself and slept, and did all that a spotted cat should do to pass the time away.

When another week had passed, she climbed the tree again and peeped into the[58] nest. This time there were five eggs.
But the spotted cat said again, “Eggs may be good, but young birds are better. I will wait a little longer!”

So she waited a little longer and then went up again to look.
Ah! there were five tiny birds, with big eyes and long necks, and yellow beaks wide open. Then the spotted cat sat down on the branch, and licked her nose and purred, for she was very happy.
“It is worth while to be patient!” she said.

But when she looked again at the young birds, to see which one she should take first, she saw that they were very thin,—oh, very, very thin they were!
The spotted cat had never seen anything so thin in her life.

“Now,” she said to herself, “if I were to wait only a few days longer, they would grow fat. Thin birds may be good, but fat birds are much better. I will wait!”

So she waited; and she watched the father-bird bringing worms all day long to the nest, and said, “Aha! they must be fattening fast! they will soon be as fat as I wish them to be. Aha! what a good thing it is to be patient.”

At last, one day she thought, “Surely, now they must be fat enough! I will not wait another day. Aha! how good they will be!”

So she climbed up the tree, licking her chops all the way and thinking of the fat young birds. And when she reached the top and looked into the nest, it was empty!!

Then the spotted cat sat down on the branch and spoke thus, “Well, of all the horrid, mean, ungrateful creatures I ever saw, those birds are the horridest, and the meanest, and the most ungrateful! Mi-a-u-ow!!!!”