Another New Mammal Big Day Record for North America

On 3 August 2014, Peter Pyle (the mastermind), Pat Kleeman and I made an all-out attempt to break the previous mammal “big day” record for North America of 30 native species, set last year by Peter Pyle, Sarah Allen and myself. We began at Point Reyes at midnight and tallied 19 species–two behind last year’s pace–by the time we reached the dock in Sausalito at 7:15 am. We added only six new species of marine mammals during a Debi Shearwater pelagic trip to the Farallon Islands and beyond. After returning from the boat trip we continued searching for mammals until 11:00 pm, finding our record-breaking 31st native species (excluding humans) at 10:35 pm. At times we were accompanied by Sarah Allen (midnight to the boat, briefly in the evening) and Gary Fellers (after the boat to the finish), who provided expert assistance on where to search for selected species.

Of the 31 native species detected, 30 were detected by all. Three species were heard only. Although we used a bat detector, which converts ultrasound signals of bats to audible frequencies, to aid in the identification of bats, only one species was identified exclusively by its vocalizations. We also observed two introduced species and eight domesticated species of mammals. Just like last year, our biggest misses were Sonoma Chipmunk and Botta’s Pocket Gopher, and we also missed Bottlenose Dolphin and Dusky-footed Woodrat this year. We journeyed 173 miles by car, 90 miles by boat, and 4.5 miles by foot. Here is our list of species (English names for species, not subspecies) in three categories, arranged by the time each was first detected with the number of individuals detected and clarification given in parenthesis:

NATIVE SPECIES
1)  00:00   Northern Elephant Seal (10)
2)  00:01   Mule Deer (71)
3)  00:13   Striped Skunk (4)
4)  00:27   Raccoon (6)
5)  00:28   American Badger (4)
6)  00:42   Coyote (1)
7)  00:47   Elk (3; heard only)
8)  01:35   Mountain Beaver (2; heard only at known burrows)
9)  01:51   Black-tailed Jackrabbit
10)  02:32   Northern River Otter (2; heard only)
11)  02:12   North American Deer Mouse (2)
12)  04:02   Big Brown Bat (30)
13)  04:06   California Myotis (20)
14)  04:06   Gray Fox (2)
15)  04:21   Brazilian Free-tailed Bat (1; identified by bat detector)
16)  05:08   Townsend’s Big-eared Bat (2)
17)  06:12   Harbor Seal (95)
18)  06:16   California Vole (2)
19)  07:24   Western Gray Squirrel (2)
20)  08:14   Harbor Porpoise (50)
21)  09:36   California Sea Lion (400)
22)  10:37   Steller Sea Lion (25)
23)  11:12   Northern Fur Seal (400)
24)  14:37   Humpback Whale (3)
25)  13:30   Risso’s Dolphin (1; seen only by Peter Pyle)
26)  17:27   Muskrat (1)
27)  17:49   California Ground Squirrel (1)
28)  19:38   Brush Rabbit (2)
29)  20:48   Yuma Myotis (2)
30)  22:28   Pallid Bat (10)
31)  22:35   Fringed Myotis (1)

INTRODUCED SPECIES
32)  00:21   House Mouse (1; captured by a Domestic Cat!)
33)  00:29   Virginia Opossum (1)

DOMESTICATED SPECIES
34)  00:13   Cattle
35)  00:16   Domestic Cat
36)  00:16   Domestic Dog
37)  04:35   Horse
38)  18:21   Sheep
39)  18:24   European Hare
40)  18:28   Llama
41)  18:29   Goat

Floyd E. Hayes
Department of Biology,
Pacific Union College
Angwin, California, USA