At the sighting, I was taken by the striking color of the males and of course, the amazing spoonbill. These birds are so front-loaded it looks like the weight of the bill should topple them over.
When I got home and began to look at the pictures, I realized that not all the males looked alike. One was clearly a fully mature Northern Shoveler in breeding plumage and the other two were not. Three observations (taken from the field guide) led me to this conclusion: The mature, male Northern Shoveler has a clear white breast, yellow eye and green head. So, I wondered if the other two might be immature. I began reading about this species. Sifting through the online info, I found information that led me to think that among this group there was one mature, one immature (first cycle), and one mature male coming out of its eclipse plumage. This conclusion is not definitive, mind you, but here is why I think this might be so:
This shot shows a fully mature pair of Northern Shovelers, both male and female. This experience with four Northern Shovelers in one locations with different plumage provided a great learning experience to better understand the plumage transitions. Since we don't get to see this species everyday, I was quite happy they all didn't look the same which motivated me to attempt to learn why.