Green Heron ' .. - ' 



The green .iieron, or "fiy-up-t he-creek", is probably the most familiar- 

 of the aiiall herons, as it ranges throughout the United States and its usual 

 taitieness makes it an object of interest to a large group of lovers of the 

 wooded streams. It appears to prefer tree-bordered channels to open marshes 

 or lake margins, 



A study of the food of 277 of these herons, collected throughout their 

 range, reveals that the angler and commercial fisherman have little to fear from 

 its feeding activities* Only a little more than one-t\ventieth of its diet was 

 found to be composed of fishes prized as human food. Most of these were sun- 

 fish and pickerel, and a large part of them, xvere found in stomachs collected 

 around the ponds of a Missouri fish hatchery. But even' in the series of 23 

 birds collected at hatchery ponds, valuable fishes made up less than one-sixth 

 of the food, v/hile such enemies of fish' fry as the crawfish made up 47,57 per- 

 cent of their diet, and aq.uatic insects, including a large proportion of 

 dragonfly nymphs, predaceous diving-beetle larvae, and large water bugs 

 ( Belostoma sp.) , also enemies of fry, formed 22.09 percent of the food. Thus 

 the herons' valuable work in eliminating many. natural enemies of fish fry 

 probably compensated for the few "pan fish" taken at this hatchery. The ■ ■ 

 following summtary of the food of the green horon. is based on laboratory examina- 

 tion of 255 well-filled stomachs: Fishes of little or no coFim.ercial value, 

 principally killifishes, m-innovjs, gobies,, and silversides, 38.52 percent; 

 valuable fishes, chiefly sunfish, pickerol, and a few bass (no trout fo'und in- 

 tha entire series), 5.91 percent; undeterm.ined fragments of fishes, 0.96 per- 

 cent; crustaceans (principally crai-Jfishes) , 20.64 percent; and insects (chiefly 

 dragonfly nj-mphs, aquatic bugs, aquatic beetles', and grasshoppers), 23.65 per- 

 cent. Spiders and miscellaneous invert ebrat-es made up the remaining small 

 percentage. . . : . ' • 



Thus- it -appears that this little heroa is worthy of rigid protection - 

 under natural conditions, and even at the sem.inatural hatchery, ponds it seems 

 occasionally at least to be destroying far more predators of fr-y-than it does 

 valuable fishes. This remark would not apply, hov;ever, to artificial ponds 

 where these predators are kept under strict control. 



Black-crowned Night, Heron 



The black-crowned night heron, the nocturnal feeding habits of which are- 

 well known throughout the entire country, is occasionally reported to cause'' 

 some destruction of valuable fishes at hatcheries,- Under natural conditions, 

 however, there is- little to fear .from its feeding activities. The contents of 

 117 stomachs, collected from, the Atlantic to the Pacific and from Canada to 

 the Gulf of Mexico, and studied, by tha Fish, and Wildlife Service, indicate an 

 extremely varied diet, Vfcile fish miade .up 51„53 percent of its food, the 

 quantity of game species vjas negligible, and. pan fishes- or valuabl-e commercial 

 species (chiefly bullheads, yellov; perch, sunfish, pickerel-, and flounders) 

 formed- only .12o?.. percent., ^vhereas fishes of low. commercial value- and unimportant 

 .or destructive species (priiicipally minnows,- killifishes, suckers, carp, and 

 river herring} composed 37,1 percent;: the remaining 1,73 percent of fish was 

 too completely digested to be identified, , In. addition to these item.s it was - 

 found that nearly 22 percent of the food was m.ade up- of crustaceans (crawfishes, 

 crabs, and shrim.ps) ; more than 16 percent of aquatic insects, including many 

 species known to be predaceous on fish fry; more than 6 percent of frogs; 



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