Octorara Lake has been a great spot to see Northern Pintails this year. The last time I checked the area off of Mt Eden Rd, there were probably close to one thousand pintails feeding there. I was looking for a previously reported Eurasian Wigeon but struck out on that.  Eurasian Wigeons have made quite a showing in PA this year, with sightings in at least Lancaster, Berks, Delaware counties.

Here is a list of the other birds I saw at Octorara Lake-

• Canada Goose – Branta canadensis     300
• Wood Duck – Aix sponsa     1
• American Wigeon – Anas americana     4
• American Black Duck – Anas rubripes     12
• Mallard – Anas platyrhynchos     30
• Northern Pintail – Anas acuta     900
• Ring-necked Duck – Aythya collaris     56
• Hooded Merganser – Lophodytes cucullatus     4
• Common Merganser – Mergus merganser     120
• Great Blue Heron – Ardea herodias     1
• Black Vulture – Coragyps atratus     4
• Turkey Vulture – Cathartes aura     8
• Bald Eagle – Haliaeetus leucocephalus     2
• Red-tailed Hawk – Buteo jamaicensis     1
• American Kestrel – Falco sparverius     1
• Ring-billed Gull – Larus delawarensis     60
• Herring Gull – Larus argentatus     3
• Mourning Dove – Zenaida macroura     2
• Belted Kingfisher – Megaceryle alcyon     1
• Red-bellied Woodpecker – Melanerpes carolinus     1
• Downy Woodpecker – Picoides pubescens     1
• Northern Flicker – Colaptes auratus     2
• Blue Jay – Cyanocitta cristata     4
• American Crow – Corvus brachyrhynchos     20
• Carolina Chickadee – Poecile carolinensis     3
• Tufted Titmouse – Baeolophus bicolor     2
• White-breasted Nuthatch – Sitta carolinensis     1
• Carolina Wren – Thryothorus ludovicianus     3
• Winter Wren – Troglodytes troglodytes     2
• Golden-crowned Kinglet – Regulus satrapa     2
• Eastern Bluebird – Sialia sialis     2
• American Robin – Turdus migratorius     19
• Northern Mockingbird – Mimus polyglottos     1
• European Starling – Sturnus vulgaris     20
• Field Sparrow – Spizella pusilla     1
• Song Sparrow – Melospiza melodia     8
• White-throated Sparrow – Zonotrichia albicollis     12
• Dark-eyed Junco – Junco hyemalis     80
• Northern Cardinal – Cardinalis cardinalis     4
• Red-winged Blackbird – Agelaius phoeniceus     120
• Common Grackle – Quiscalus quiscula     800
• House Finch – Carpodacus mexicanus     3
• Pine Siskin – Carduelis pinus     16
• American Goldfinch – Carduelis tristis     X

Location:     Lancaster County Central Park
Observation date:     5/8/08
Number of species:     58

Wood Duck – Aix sponsa     2
Double-crested Cormorant – Phalacrocorax auritus     1
Osprey – Pandion haliaetus     1
Red-tailed Hawk – Buteo jamaicensis     1
Solitary Sandpiper – Tringa solitaria     2
Rock Pigeon – Columba livia     X
Mourning Dove – Zenaida macroura     X
Chimney Swift – Chaetura pelagica     X
Red-bellied Woodpecker – Melanerpes carolinus     X
Hairy Woodpecker – Picoides villosus     1
Olive-sided Flycatcher – Contopus cooperi     1
Eastern Wood-Pewee – Contopus virens     2
Eastern Phoebe – Sayornis phoebe     2
Great Crested Flycatcher – Myiarchus crinitus     2
Eastern Kingbird – Tyrannus tyrannus     6
Blue-headed Vireo – Vireo solitarius     1
Warbling Vireo – Vireo gilvus     X
Red-eyed Vireo – Vireo olivaceus     X
Blue Jay – Cyanocitta cristata     X
American Crow – Corvus brachyrhynchos     X
Tree Swallow – Tachycineta bicolor     X
Carolina Chickadee – Poecile carolinensis     X
House Wren – Troglodytes aedon     X
Blue-gray Gnatcatcher – Polioptila caerulea     2
Eastern Bluebird – Sialia sialis     2
Wood Thrush – Hylocichla mustelina     8
American Robin – Turdus migratorius     X
Gray Catbird – Dumetella carolinensis     5
Northern Mockingbird – Mimus polyglottos     1
European Starling – Sturnus vulgaris     X
Yellow Warbler – Dendroica petechia     1
Chestnut-sided Warbler – Dendroica pensylvanica     2
Magnolia Warbler – Dendroica magnolia     2
Black-throated Blue Warbler – Dendroica caerulescens     2
Yellow-rumped Warbler – Dendroica coronata     4
Black-throated Green Warbler – Dendroica virens     2
Yellow-throated Warbler – Dendroica dominica     1
American Redstart – Setophaga ruticilla     1
Ovenbird – Seiurus aurocapilla     5
Common Yellowthroat – Geothlypis trichas     3
Hooded Warbler – Wilsonia citrina     1
Scarlet Tanager – Piranga olivacea     X
Eastern Towhee – Pipilo erythrophthalmus     X
Chipping Sparrow – Spizella passerina     X
Field Sparrow – Spizella pusilla     X
Grasshopper Sparrow – Ammodramus savannarum     1
Song Sparrow – Melospiza melodia     X
White-throated Sparrow – Zonotrichia albicollis     10
Northern Cardinal – Cardinalis cardinalis     X
Rose-breasted Grosbeak – Pheucticus ludovicianus     5
Indigo Bunting – Passerina cyanea     X
Red-winged Blackbird – Agelaius phoeniceus     X
Common Grackle – Quiscalus quiscula     X
Brown-headed Cowbird – Molothrus ater     X
Orchard Oriole – Icterus spurius     8
Baltimore Oriole – Icterus galbula     6
American Goldfinch – Carduelis tristis     X
House Sparrow – Passer domesticus     X

This report was generated automatically by eBird v2(http://ebird.org/pa)

Snow Geese flock, originally uploaded by topherous.

Cornell Lab of Ornithology’s eBird site has just posted Bird Counting 101. For anyone who spends time out in the field watching large flocks, whether they are shorebirds, waterfowl or hawks knows that estimating flock size can be ridiculously hard. Just looking at the flock of Snow Geese above is overwhelming if you want to try and estimate the number of birds. Estimating sizes of flocks can be biologically important because it is an additional data set that can be more useful than just knowing whether a species is present or absent.

Cornell puts forth several different tips for counting in their first installment:

1. It is very important to write your observations down right away. No one can remember counts for 40+ species at a time. You will also end up second guessing yourself if you don’t write down what you see, particularly with the more common species, “Did I really see a Mourning Dove today or was that yesterdays walk?”
2. Be conservative in your estimates, making sure you are not counting birds twice.
3. For larger flocks, count a small portion of the flock and then extrapolate for the rest of the flock. For instance, count 10 birds in the flock and get a good idea of what that feels like. Then count the flock in 10 bird increments. This fall I was the counter on South Lookout at Hawk Mountain Sanctuary, PA on the morning that a flight of over 5,000 Broad-winged Hawks migrated through. I mainly counted in 5 and 10 bird increments because the birds kept coming and coming and coming.

One fascinating fact from the article was that we have a hard time estimating flocks when they are flying in 3D space. If a large blackbird flock is 100 birds wide, 100 birds long, and 100 birds deep, that is 1,000,000 blackbirds! I have a hard time imagining that.

Check out the full article.