Pelecanus erythrorhynchos By Matt Young October 24, 2016 12:00 MST Pelecanus erythrorhynchos – American white pelican, Walden Ponds, Boulder, Colorado, July 16, 2016. Mea culpa: The birds were just beyond the limit of my equipment, but this was the first time I recall seeing pelicans so late in the season and certainly the first time I have seen a juvenile. It may be sampling error – I do not visit Walden Ponds every week – but I wonder whether they are changing their migration patterns as the climate warms.