August is very hot in the Barrens.This is an understatement.You'll find most critters in or near water.The cedar and maple swamps mostly.Most mammals like anywhere else are nocturnal and especially so in the heat of summer..Reptiles can be found anywhere but many also are nocturnal and hang out near water.Amphibians are pretty much tied to water and are nocturnal and many can be found by vocalizations.Birds happily for the most part are diurnal excepting owls and a few others.Birds and any animal you find out and about in the day will most likely be moving at Dawn and dusk when it's cooler.This is known as "crepuscular" activity.Now insects are out at all hours.Some of our not so pleasant inhabitants are Deer Flies,various species of Ticks,Chiggers,Mosquitoes,and Greenheads in the salt marshes and beaches.Also it's dragonfly and butterfly season and these do turn out in the heat of the day,moths at night.You'll hear cicadas mostly in the day or dusk and katydids are about to debut at night,in august they will be out in full force.Most common birds are Northern Towhees,Ovenbirds,Blue Jays,Crows,Chickadees,Juncos,various Warblers and Sparrows,in the wetter areas red Winged Blackbirds,Great Blue herons ,Green herons,etc. All in all if you want critters you'll do better near water at dawn and dusk.We have White tail Deer and lately a few introduced Black Bear.Also Coyotes commonly heard at night though seldom seen and Bobcat hardly ever seen.We have Rattlers ,very uncommon and Pine snakes more common and diurnal as a bonus.Fish species in the core barrens are limited.Pickerel in streams and lakes, bass in some lakes and sunnies in the blueholes,Tidal creeks have carp as well.What critters are you talking about specifically?