About Pilherodius pileatus (Boddaert, 1783)
Pilherodius pileatus, commonly called the capped heron, is easily distinguished from all other heron species. It is the only heron with a blue beak and blue face, paired with a black crown. Three to four long white feathers extend from its black crown. The neck, chest, and belly are covered in yellowish-white or light cream-colored feathers, while the back and wings are covered in white feathers. No sexual dimorphism in feather color or brightness has been recorded for this species. Adult body length ranges from 510 to 590 mm, wing chord length ranges from 263 to 280 mm, tail length ranges from 95 to 103 mm, and tarsus length ranges from 92 to 99 mm. Adult body weight ranges from 444 to 632 g. Juvenile capped herons are very similar in appearance to adults, differing only in smaller body size and having a slight grey tinge to their white feathers. The capped heron is endemic to the Neotropics, and is almost exclusively found in rainforest. It occurs in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Panama, Paraguay, Peru, Suriname, and Venezuela. It generally inhabits low elevation areas up to 900 m above sea level; it is restricted to areas below 500 m in Venezuela, and below 400 m in Ecuador. No long-distance migrations have been recorded for this species, and it is thought to be generally sedentary, though seasonal local movements may occur in Darien, Panama. It most often lives in swamps and ditches within wet grasslands or rainforest, and can sometimes be found in deeper ponds and rivers. It prefers to forage along shorelines or on floating vegetation, but has also been observed foraging in trenches on coffee plantations and in flooded rice fields. Capped herons hunt primarily for fish, and also eat aquatic insects, insect larvae, tadpoles, and frogs. Most fish prey caught by this species are between 1 and 5 cm long. They hunt insects in vegetation near rivers or ponds, and hunt fish in shallow water. A typical capped heron hunting sequence begins with the heron standing upright to search for prey. Once prey is located, the heron slowly crouches and extends its neck, then quickly stabs its beak into the water to catch the prey. The observed hunting success rate for this sequence is 23%. Capped herons can also use this same hunting sequence while walking through shallow water. They usually walk slowly, repeatedly covering the same area, pausing for a few seconds before slowly moving one foot to take a new step. There are recorded observations of individual capped herons using other hunting behaviors including aerial hunting, peaking, gleaning, foot paddling, dipping, swimming feeding, and bill-vibrating. Capped herons move often between feeding sites, and sometimes fly up to 100 m between sites. They may be crepuscular, but have also been observed foraging in full daylight, unlike night-herons. They most often hunt alone.
