It was difficult to keep the blocks up to date in the Hummingbird library, and we also rolled out a webapp for Hummingbird in Snap! that used a somewhat different set of blocks such that if you loaded the Hummingbird library while using our webapp, the Hummingbird blocks would not work. For those reasons, we asked for it to be removed. You can access the blocks directly by going to the following link:
https://snap.berkeley.edu/snap/snap.html#present:Username=birdbraintech&ProjectName=HummingbirdSingleDeviceStarterProject&editMode&noRun&lang=en