Good question, the easy answer is both. Both the large bears you will see in Alaska and the smaller bears you might have seen at Yellowstone are not only the same species, but the same subspecies, Ursus arctos horribilis. The brown bears found on Kodiak are considered a different subspecies, primarily because of some differences in the skull. In general, bear biologists and those interested in bears tend to call the bears in Alaska brown bears, and those found in the Northern Rockies of the United States and Canada Grizzlies. The term grizzly comes from the silver tipped hair of the bears in the Rockies.
However, based on sizes, diet, and home ranges some biologists have recommended designating 3 groups of brown bears whose ranges are mapped below. The 3 groups described from studies of 25 different populations were the Coastal, the inland, and the barren ground brown bears. In Alaska, both in Katmai and Silver Salmon Creek, you are seeing the Coastal Brown, the largest of any of the brown bears found in North America or the world. There are large coastal brown bears in the former Soviet Union in Kamchatka as well.
(From Effect of energy availability, seasonality, and geographic range on brown bear life history by Steven H. Ferguson and Philip D. McLoughlin; Ecography, Copenhagen, 2000.)
I have been spending a couple weekends so far shooting birds from blinds at 2 locations run by friends of mine that offer excellent chances to photograph a variety of species at close range in just a morning or 2. I first want to tell you about Bill Forbes' Elephant Head Pond on his property in Amado, Arizona, approximately 40 miles south of Tucson. In just 2 mornings and one afternoon I was able to photograph 22 species and have over 100 "keepers" that I need to continue processing.
I was able to shoot several shots of each of the following species: Gambel's Quail, Mourning, White winged and Inca Doves, the Eurasian Collared Dove, Gila and Ladder-backed Woodpeckers, Verdin, Cactus Wren, Curve-billed Thrasher, Pyrrhuloxia, Northern Cardinal, Canyon Towhee, Brewer's Sparrow, Cassin's Sparrow, Black-throated Sparrow, English House Sparrow (hey, it's a bird right?), Chipping Sparrow, Lark Sparrow, White Crowned Sparrow, Brown Headed Cowbird, and the House Finch. You can view a representation of what I shot here (just click here). I was happy to have such a good representation of the High Sonoran Desert birds from right at the base of the Santa Rita Mountains. Bill will get an influx of several more species but I knew that at this time of year I would be lucky to get any thing but residents and some wintering sparrows. That's what I got and I got 95% of what I could hope for.
There were a few broad billed and black chinned hummingbirds around but I didn't have the time to do a set up for them. His place is great for that as it warms up and more birds arrive.
Bill's nice water feature, built for bird and bat photography, with blinds all around and several feeders that are filled twice a day make for excellent opportunities to shoot. He also has a series of nice perches ranging for live cholla growing in a wheel barrow to saguaro skeletons that can be set up as you wish. I also had clipped and brought some lower elevation wildflowers and flowering shrubs that I keep in flower tubes to add to the background and you might want to do the same. His location at the base of the Santa Rita's and just a "stones throw" from Madera Canyon ensure the birds will be there. I have shot there at several different times of the year and I'm well aware of why well known photographers such as the McDonalds or Allen Murphy use his location (s) for some of their photo tours. He also has a location reserved in Madera Canyon just across from the Santa Rita Lodge and a couple new friends and I will shoot there in mid April. Look for my report on that in a month or so.
Although I have every intention of leading tours there where I help people better their skills and get some great bird images you don't have to go with me. Especially if you feel comfortable on your own. Book early though as his places fill up at the prime time for our SE nesting species and migrants. You can easily reach Bill by calling him at 520 444-6649 and/or check out his website at phototrap.com. If you do call him please tell him I referred you as Bill has been very good to me and I want him to know I appreciate it.