Summary - Bird Mountain, in the Indian Heaven Wilderness, combines good trails and a steep bushwhack (not for beginners). While makes for a longish day, link it with Lemei Rock for a two summit, twelve point outing. The trip from Portland to the Cultus Creek Campground (day fee or pass required) is about two hours on mosly paved roads. ATT digital service is good, as is APRS. The trail from the campground to the summit trail is in good shape and very popular. The summit trail involves a lot of bushwhacking and is steep.
TL;DR - Bird Mountain is a mostly intact shield volcano in the Indian Heaven Wilderness. I combined it with Lemei Rock by hiking in from Cultus Creek Campgound on Indian Heaven trail #33 (I did Lemei first). The trail in is well-maintained and quite popular. There is no trail, user or otherwise, to the summit. The terrain is complex; choose the wrong way up and you end up under a cliff band, in a gully, or blocked by thick bands of young trees. Any way up involves negotiating steep sections, rock outcroppings, snags, and sometimes thick brush. You must be comfortable using a map, compass, and taking bearings on this one.
Most of the available beta suggests leaving the Indian Heaven trail at roughly (46.03146, -121.77429) and climbing northwest toward the saddle at the south end of Bird's lower summit. Once there, work your way around to the west on steep terrain to bypass the first summit and then climb to the northeast (46.03650, -121.78007) to the second saddle between the lower and higher summit. Once in the saddle, traverse the open ground along the forest edge to the ridge up to the summit proper.
On top, you will have views of all your favorite volcanoes and the other Indian Heaven SOTA peaks. Take a mast if you want to do HF. You are unlikely to have company up here. ATT digital service was very good and was APRS; I was able to spot using both. I did not try VHF but my experience on other mountains in this area suggests it is usable with a good antenna. When you finish work your way back down the way you came up.
From Portland, I took I84 to the Bridge of the Gods to Carson to Wind River Highway. The drive to the campground took a little more than two hours. Note that the trailhead for Indian Heaven #33 starts at the day parking area, not the campground, and requires a NW Discover Pass, its equivalent, or five dollars in the self-pay box. This is also a wilderness area and requires a self-issued permit. This is a popular trail and area. You will encounter other hikers, on the weekend at least, and probably - as I did - have company on the summit.
Combine Bird Mountain with Lemei Rock, also along this trail, for a longish day with two challenging bushwhacks, two nice views, and twelve SOTA points. Both require off trail skills, being comfortable with negotiating steep, brush, snags, and often complex terrain.