CHAPTER 1 DELAWARE’S WILDLIFE SPECIES OF GREATEST CONSERVATION NEED CHAPTER 1: Delaware’s Wildlife Species of Greatest Conservation Need Contents Introduction ................................................................................................................................................... 7 Regional Context ........................................................................................................................................... 7 Delaware’s Animal Biodiversity .................................................................................................................... 10 State of Knowledge of Delaware’s Species ................................................................................................... 10 Delaware’s Wildlife and SGCN - presented by Taxonomic Group .................................................................. 11 Delaware’s 2015 SGCN Status Rank Tier Definitions................................................................................. 12 TIER 1 .................................................................................................................................................... 13 TIER 2 .................................................................................................................................................... 13 TIER 3 .................................................................................................................................................... 13 Mammals ..................................................................................................................................................... 14 Mammal Diversity of Delaware ................................................................................................................ 14 Delaware SGCN Mammals ....................................................................................................................... 14 Carnivores ............................................................................................................................................ 14 Small Mammals .................................................................................................................................... 15 Bats ...................................................................................................................................................... 16 Marine Mammals .................................................................................................................................. 18 Birds ............................................................................................................................................................ 19 Avian Diversity of Delaware...................................................................................................................... 19 Regional, National, and International Perspectives .................................................................................. 21 Regional Species of Greatest Conservation Need (RSGCN)................................................................... 21 Audubon Important Bird Areas ............................................................................................................. 21 Bird Conservation Regions .................................................................................................................... 21 Delaware SGCN Birds ............................................................................................................................... 24 Waterbirds ............................................................................................................................................ 24 Landbirds.............................................................................................................................................. 39 Reptiles and Amphibians ............................................................................................................................. 51 Reptile and Amphibian Diversity of Delaware ........................................................................................... 51 1 - 2 Delaware Wildlife Action Plan Amphibians .......................................................................................................................................... 52 Snakes and Lizards ............................................................................................................................... 55 Turtles .................................................................................................................................................. 56 Fish .............................................................................................................................................................. 60 Fish Diversity of Delaware ........................................................................................................................ 60 Freshwater Fish .................................................................................................................................... 62 Diadromous Fish ................................................................................................................................... 65 Estuarine and Marine Fish ..................................................................................................................... 66 Sharks, Rays and Skates ....................................................................................................................... 69 Invertebrates ............................................................................................................................................... 72 Invertebrate Diversity of Delaware ........................................................................................................... 72 Insects .................................................................................................................................................. 72 Mollusks ............................................................................................................................................... 95 Estuarine and Marine Invertebrates ...................................................................................................... 99 Plants .......................................................................................................................................................... 101 Update and Revision of Delaware’s SGCN List ............................................................................................ 103 Summary of SGCN List Changes since 2006 ............................................................................................ 103 SGCN Selection Process .......................................................................................................................... 107 SGCN Prioritization Methods ...................................................................................................................... 112 Tier Definitions and Criteria ..................................................................................................................... 112 Species Conservation Approaches .............................................................................................................. 115 Surrogate Species ................................................................................................................................ 115 Literature Cited ........................................................................................................................................... 117 Figures Figure 1. 1 Delmarva Fox Squirrel (Sciurus niger cinereus). Photo: USFWS .................................................... 16 Photo: Shannon Alexander 1- 3 CHAPTER 1: Delaware’s Wildlife Species of Greatest Conservation Need Figure 1. 2 Map of North American Bird Habitat Joint Ventures, showing the Atlantic Coast Joint Venture (ACJV) area in light blue ................................................................... ……………………………………………………23 Figure 1. 3 Red knots (Calidris canutus) need to encounter favorable habitat, weather conditions, and food (such as the horseshoe crabs they feed upon in Delaware) within narrow seasonal windows during their migration stopovers. Photo: Harold A. Davis ................................................................................................ 26 Figure 1. 4 The piping plover (Charadrius melodus) population has been on the rise since the early 1990s, but this is due to sustained management initiatives, upon which populations remain dependent. Photo: Harold A. Davis ........................................................................................................................................................ 29 Figure 1. 5 Yellow-crowned night heron (Nyctanassa violacea). Photo: Harold A. Davis ............................... 32 Figure 1. 6 Saltmarsh sparrow (Ammodramus caudacutus). Photo: Harold A. Davis ...................................... 38 Figure 1. 7 Rusty blackbird (Euphagus carolinus). Photo: Harold A. Davis ...................................................... 51 Figure 1. 8 Barking treefrog (Hyla gratiosa) is a southeastern species that reaches the northern edge of its range in Delaware and is entirely dependent on Coastal Plain seasonal ponds for breeding habitat. Photo: Jim White ....................................................................................................................................................