These young Anhingas were doing their best to weather the light rain on a mid-July morning at the UTSWMC Rookery.
Wikipedia has this to say about Anhingas:
It is a cormorant-like bird with an average body length of 85 cm (33 in), a wingspan of 117 cm (46 in), and a mass of up to 1.35 kg (3.0 lb). It is a dark-plumaged piscivore with a very long neck, and often swims with only the neck above water. When swimming in this style the name Snakebird is apparent, since only the colored neck appears above water the bird looks like a snake ready to strike. They do not have external nares (nostrils) and breathe solely through their epiglottis.