Questions & Answers about Puistossa on viisikymmentä puuta ja viisitoista lintua.
Why does the sentence use on (is) instead of ovat (are) when there are multiple trees and birds?
Why do puu (tree) and lintu (bird) change to puuta and lintua?
They are in the partitive case. In Finnish, any number greater than one must be followed by a noun in the partitive singular form.
How is the word for fifty (viisikymmentä) formed?
Why does the sentence start with the location, puistossa?
This is the standard word order for "There is/are" sentences in Finnish. You start with the location, add the verb on, and end with what is actually there. If you started with the trees and birds instead, it would mean "The 50 trees and 15 birds are in the park."