60 birds were recorded seen in Delaware in September in our iNaturalist sample; 6 of the top 50 are at their peak this month. The list is ranked by number of research-grade observations.
Top birds in September

Laughing Gull

Great Blue Heron

Great Egret
Snowy Egret

Bald Eagle

Osprey

Double-crested Cormorant

Sanderling

American Redstart

Ruby-throated Hummingbird

American Goldfinch
Common Yellowthroat
All birds seen in Delaware in September
| # | Species | Scientific name | Family | Obs. | Peak in state |
|---|---|---|---|---|---|
| 1 | Laughing Gull | Leucophaeus atricilla | Gulls, Terns, and Skimmers | 228 | Aug (past peak) |
| 2 | Great Blue Heron | Ardea herodias | Herons, Egrets, and Bitterns | 182 | May (past peak) |
| 3 | Great Egret | Ardea alba | Herons, Egrets, and Bitterns | 156 | Aug (past peak) |
| 4 | Snowy Egret | Egretta thula | Herons, Egrets, and Bitterns | 151 | Aug (past peak) |
| 5 | Bald Eagle | Haliaeetus leucocephalus | Hawks, Eagles, and Kites | 137 | Apr (past peak) |
| 6 | Osprey | Pandion haliaetus | Ospreys | 120 | Jul (past peak) |
| 7 | Double-crested Cormorant | Nannopterum auritum | Cormorants and Shags | 97 | Aug (past peak) |
| 8 | Sanderling | Calidris alba | Sandpipers and Allies | 92 | Aug (past peak) |
| 9 | American Redstart | Setophaga ruticilla | New World Warblers | 91 | Sep (peak) |
| 10 | Ruby-throated Hummingbird | Archilochus colubris | Hummingbirds | 90 | Aug (past peak) |
| 11 | American Goldfinch | Spinus tristis | Finches, Euphonias, and Allies | 86 | Apr (past peak) |
| 12 | Common Yellowthroat | Geothlypis trichas | New World Warblers | 81 | May (past peak) |
| 13 | American Avocet | Recurvirostra americana | Stilts and Avocets | 79 | Aug (past peak) |
| 14 | Turkey Vulture | Cathartes aura | New World Vultures | 76 | Apr (past peak) |
| 15 | Red-tailed Hawk | Buteo jamaicensis | Hawks, Eagles, and Kites | 76 | Jan (past peak) |
| 16 | Green Heron | Butorides virescens | Herons, Egrets, and Bitterns | 71 | Aug (past peak) |
| 17 | Mourning Dove | Zenaida macroura | Pigeons and Doves | 69 | Apr (past peak) |
| 18 | Canada Goose | Branta canadensis | Ducks, Geese, and Swans | 69 | May (past peak) |
| 19 | Cooper's Hawk | Astur cooperii | Hawks, Eagles, and Kites | 66 | Oct (rising) |
| 20 | Broad-winged Hawk | Buteo platypterus | Hawks, Eagles, and Kites | 65 | Sep (peak) |
| 21 | Northern Cardinal | Cardinalis cardinalis | Cardinals and Allies | 62 | Apr (past peak) |
| 22 | Great Black-backed Gull | Larus marinus | Gulls, Terns, and Skimmers | 56 | Aug (past peak) |
| 23 | Semipalmated Plover | Charadrius semipalmatus | Plovers and Lapwings | 56 | Aug (past peak) |
| 24 | White Ibis | Eudocimus albus | Ibises and Spoonbills | 55 | Aug (past peak) |
| 25 | Forster's Tern | Sterna forsteri | Gulls, Terns, and Skimmers | 55 | Aug (past peak) |
| 26 | Black-and-white Warbler | Mniotilta varia | New World Warblers | 55 | Sep (peak) |
| 27 | Mute Swan | Cygnus olor | Ducks, Geese, and Swans | 53 | May (past peak) |
| 28 | Mallard | Anas platyrhynchos | Ducks, Geese, and Swans | 53 | May (past peak) |
| 29 | Greater Yellowlegs | Tringa melanoleuca | Sandpipers and Allies | 51 | Apr (past peak) |
| 30 | Northern Parula | Setophaga americana | New World Warblers | 51 | Sep (peak) |
| 31 | Red-shouldered Hawk | Buteo lineatus | Hawks, Eagles, and Kites | 50 | Jan (past peak) |
| 32 | Blue Grosbeak | Passerina caerulea | Cardinals and Allies | 50 | May (past peak) |
| 33 | Caspian Tern | Hydroprogne caspia | Gulls, Terns, and Skimmers | 50 | Aug (past peak) |
| 34 | Blue Jay | Cyanocitta cristata | Crows, Jays, and Magpies | 49 | Apr (past peak) |
| 35 | Gray Catbird | Dumetella carolinensis | Mockingbirds and Thrashers | 47 | May (past peak) |
| 36 | Red-eyed Vireo | Vireo olivaceus | Vireos, Shrike-Babblers, and Erpornis | 47 | Sep (peak) |
| 37 | American Herring Gull | Larus smithsonianus | Gulls, Terns, and Skimmers | 46 | Feb (past peak) |
| 38 | Brown Pelican | Pelecanus occidentalis | Pelicans | 44 | Jul (past peak) |
| 39 | Peregrine Falcon | Falco peregrinus | Falcons and Caracaras | 44 | Oct (rising) |
| 40 | Carolina Chickadee | Poecile carolinensis | Tits, Chickadees, and Titmice | 44 | Apr (past peak) |
| 41 | Wild Turkey | Meleagris gallopavo | Pheasants, Grouse, and Allies | 43 | Apr (past peak) |
| 42 | Northern Harrier | Circus hudsonius | Hawks, Eagles, and Kites | 43 | Dec (rising) |
| 43 | Northern Mockingbird | Mimus polyglottos | Mockingbirds and Thrashers | 42 | Apr (past peak) |
| 44 | Carolina Wren | Thryothorus ludovicianus | Wrens | 41 | May (past peak) |
| 45 | Black-bellied Plover | Pluvialis squatarola | Plovers and Lapwings | 38 | May (past peak) |
| 46 | Royal Tern | Thalasseus maximus | Gulls, Terns, and Skimmers | 38 | Aug (past peak) |
| 47 | Roseate Spoonbill | Platalea ajaja | Ibises and Spoonbills | 37 | Sep (peak) |
| 48 | Downy Woodpecker | Dryobates pubescens | Woodpeckers | 37 | Feb (past peak) |
| 49 | Lesser Black-backed Gull | Larus fuscus | Gulls, Terns, and Skimmers | 36 | Oct (rising) |
| 50 | House Finch | Haemorhous mexicanus | Finches, Euphonias, and Allies | 36 | May (past peak) |