No, I don't think native birds prefer non-native berries. Another reason to give native vegetation primary consideration when choosing berry plants is the local birds have evolved along with these plants. Consequently, native varieties are better adapted to providing local birds with the nutrition they need. It is possible over time that plants like these out-compete native plants and they become the primary source of food because there is so little else. But that is just a vicious circle. I do believe that birds (native ones) prefer the native berries that they have evolved with over thousands of years. You may be seeing non-native birds eat these berries (starlings, grackles are non-native birds). But for native birds, these would be a food of "last resort". And don't forget my earlier point that non-native plants don't support the native insects which are an important source of protein for birds. More non-native plants = lower insect population = lower bird population. Here is a link that might be useful: Source of above quote

Indian plum, Oemleria cerasiformis. White flowers in very early spring, purple fruit which the birds love. Here is a link that might be useful: oemleria

Post a picture of the bark and the tree as a whole.

Something showing scale would help. How big are those fruit? The leaves don't look right for C speciosa imo. Nor do the thorns. I very tentatively suggested C cathayensis on the OP's duplicate thread. It should flower soon. Perhaps you can come back with more pictures?