Probably raised from seed if 4' tall, will be some years yet before it reaches sexual maturity. Cross-pollination not required.

They bloom when young, maybe 5 or 6 years. The flowers smell funny, like something and bleach. The fruit have to turn black (ferment) before the birds eat them, typically around here that is the spring.

Watch for Cedar-Apple-Wheat rust. It kills the twigs where the fungus makes the knot. Getting rid of a Juniper helped in my case, the juniper was really contributing to rust. I have 2 of these trees (Crataegus), soon only one. Not my favorite tree by far.

Would you put another tree in it's place?

If so what would you put in it's place?

Green hawthorn (Crataegus viridis), especially the cultivar 'Winter King', is probably the most rust-resistant of the hawthorns. The cockspur hawthorn (wild) behind my garden gets completely defoliated by September every year, sooner if it's a wet summer...

Why I planted this tree was because I wanted to have birds in my backyard.

Is there a better tree that would bring Cardinals to your backyard?

Also plant oaks because they support a lot of moths and butterflies that lay eggs on them; those make caterpillars and many birds are insectivores. Plus birds need caterpillars to feed their babies.

There's a whole world of "bird feeding" beyond seeds and berries.