A NEW MAMMAL BIG DAY FOR NORTH AMERICA

Howdy, Birders,

Below, please find a report on a new MAMMAL BIG DAY FOR NORTH AMERICA on August 4, 2004 by Sarah Allen, below and Peter Pyle, below on right and Floyd Hayes, below on left. Part of their day included the Shearwater Journeys' pelagic trip to the Farallon Islands.

On 4 August, Peter Pyle (the mastermind), Sarah Allen and I made an all-out attempt to break the previous mammal “big day” record for North America of 17 native species, set independently by Peter Pyle and Richard Stallcup. We began at Point Reyes at midnight and managed to break the record before dawn, recording our 18th species at 5:25 am! By the time we reached the dock in Sausalito at 7:15 am we had already tallied 21 species. We added 7 new seven species of marine mammals during a Debbie Shearwater pelagic trip to the Farallon Islands, where we saw the lingering NORTHERN GANNET (obviously our best bird of the day). After returning from the boat trip we spent another 6 hours searching for mammals but added only 2 more species, finishing our big day at 10:20 pm with 30 native mammals (29 detected by all; 3 heard only), 3 introduced mammals and 5 domesticated mammals. We used a bat detector, which converts ultrasound signals of bats to audible

frequencies, to aid in the identification of bats at known roosts. Our biggest misses were Coyote, Badger, Gray Whale, Blue Whale, Sonoma Chipmunk and Muskrat. We journeyed 171 miles by car in a Toyota Prius, 90 miles by boat and 2 miles by foot. Here is our list of species in three categories, arranged by the time each was first detected:

NATIVE SPECIES

1) 00:01 Mule Deer

2) 00:06 Northern Elephant Seal

3) 00:12 Striped Skunk

4) 00:33 Raccoon

5) 00:50 Elk

6) 01:09 Brush Rabbit

7) 01:29 Deer Mouse

8) 01:33 Bobcat

9) 01:55 Pacific Jumping Mouse

10) 02:10 River Otter (heard only)

11) 03:11 Gray Fox

12) 03:35 Brazilian Free-tailed Bat

13) 03:41 Black-tailed Jackrabbit

14) 04:10 Pallid Bat

15) 04:15 California Myotis (heard only)

16) 04:18 Big Brown Bat

17) 04:48 Dusky-footed Woodrat (heard only)

18) 05:25 Townsend's Big-eared Bat

19) 06:05 Harbor Seal

20) 06:11 Meadow Vole

21) 06:55 Western Gray Squirrel

22) 08:20 Harbor Porpoise

23) 10:30 California Sea Lion

24) 10:30 Steller's Sea Lion

25) 11:25 Northern Fur Seal

26) 12:02 Dall's Porpoise

27) 12:31 Humpback Whale

28) 15:33 Pacific Bottlenose Dolphin

29) 18:18 California Ground Squirrel

30) 19:55 Yuma Myotis

INTRODUCED MAMMALS

31) 12:58 Virginia Opossum

32) 04:41 Fallow Deer

33) 05:25 Human

DOMESTICATED MAMMALS

34 00:30 Cattle

35 03:51 Dog (heard only)

36 05:05 Horse

37 05:57 House Cat

38 18:32 Goat

Floyd Hayes