Online cultural heritage collections often contain complementary objects, which makes integration between heterogeneous collections a worthwhile effort. In order to do so, objects have to be adequately described. Crowdsourcing in cultural heritage is evolving to be an approach to collect annotations at scale, but faces challenges regarding sustainability and structured use of results in the context of existing collections. The DigiBird project integrates four distinct nature-related collections and serves as a hub for crowdsourcing systems that extend collection data. An Application Program Interface (API) is built on top of the DigiBird pipeline, enabling institutions to embed integrated results in their online collections.