By Jennifer Nixon, Denver Zoo Bird Keeper
In honor of Mother’s Day we would like to introduce this week’s rather secretive Feathered Friend and mother, Walda. She is a boat-billed heron (Cochlearius cochlearius ridgwayi) and is the proud mother of all the boat-billed herons at Denver Zoo. She lives in the Rainforest room of Bird World, sponsored by Frontier Airlines, with her two daughters, who are now 2 years old. In the Aquatics room further along in the building, she has two sons age 2 and 4 years old. She is 22 years old and has been very busy in her life. She has reared a total of 11 chicks and is a very attentive mother. In this picture she can be seen sitting on the nest from her last clutch of chicks in 2012. She is not really secretive but she is nocturnal and sleeps in the canopy most of the day. You can find her in her favorite spot, if you know where to look! You can usually see her if you stand next to the tree across from the waterfall and look up into the skylights. Sometimes you can look for her for ages, just to find her staring back down at you.
Boat-billed herons live in mangrove swamps from Mexico south to Peru and Brazil. They get their name from their wide scoop-like bills used for catching food. Originally they were placed in their own family Cochleariidae that included only boat-billed herons due to their very uniquely shaped bill. They were later reclassified to family Ardeidae which includes other herons and egrets. All Ardeidae members, other than the boat-billed herons, have long pointed bills used for spearing or snatching prey. The close relationship was only found when comparing the skull of a boat-billed heron to the black-crowned night heron (Nycticorax nycticorax ). They are also more distantly related to pelicans and belong to the order Pelecaniformes. There are several theories to explain the shape of the bill. Most lack supporting evidence and the most likely theory is that the wide bill compensates for the inaccuracy of hunting at night, or it could be used for producing sound during courtship. Their beaks make a loud clacking noise when they snap it shut.
We invite you to come play “Where’s Walda” in the Rainforest room of Bird World on your next visit to Denver Zoo. The building feels warm in the winter and cool in the summer so it is a good place to relax on any temperature day.