Songbirds and Russian Olive Berries

Cedar Waxwings feeding on Russian olive berries

Yellow-rumped Warbler feeding on Russian olive berries

Currently, we are categorizing the berry production on selected Russian olive (exotic vegetation) and New Mexico olive (native vegetation) plants located on transects in our middle Rio Grande study area. The berries of these two plants provide an important food source for wintering (and to a lesser extend, migrating) birds that frequent the middle Rio Grande bosque. Russian olive berries are particularly important to wintering birds because they remain a viable food source throughout the winter or until the resource is depleted. In contrast, New Mexico berries tend to desiccate as winter progresses, and become a decreasingly useful food source. To date, we have documented over 30 bird species foraging on Russian olive berries, and a similar number exploiting New Mexico olive. Ultimately, we hope to generate a long-term berry production data set (10+ years) that can be compared to environmental conditions (i.e. weather patterns, river flow levels, etc.) to gain insight regarding factors that impact berry crop size in the middle Rio Grande bosque. -- written by Trevor Fetz, avian biologist

Fall Songbird Migration - Albuquerque Bosque

MacGillivray's Warbler. Photo by Doug Brown.

Fall migration is now clearly in full swing. Large numbers of MacGillivray’s Warbler, Yellow Warbler, and Virginia’s Warbler are currently moving through the bosque. Wilson’s Warbler numbers are currently comparable to those of the three warblers mentioned above, but are small compared to the numbers that will be present in the bosque during the coming weeks. Orange-crown Warbler and Townsend’s Warbler are also moving through in relatively large numbers. Western Wood-Pewee numbers have greatly increased this week compared to earlier in the month. We undoubtedly undercount vireos in the bosque because they rarely vocalize during this time of year, but we have recorded three species so far this week. Warbling Vireos are regular right now, and we finally detected our first Plumbeous Vireos this week. Most exciting, however, is the detection of three Red-eyed Vireos over the past eight days, a species that is normally very rare in the bosque.

Songbird Migration Is On!

Yellow Warbler. Photo by David Powell.

Migration is beginning to pick up steam in the bosque. Among warblers, Yellow Warblers are currently moving through in the largest numbers, with smaller numbers of MacGillivray’s Warblers and Virginia’s Warblers also popping up. Wilson’s Warblers are just starting to trickle into the bosque, and we have also recorded Black-throated Gray Warbler and Orange-crowned Warbler over the past week. Other migrants currently moving through include Western Tanager, Warbling Vireo, Rufous Hummingbird, Broad-tailed Hummingbird, Calliope Hummingbird, and Gray Flycatcher. Other species of note include Lark Sparrow and Chipping Sparrow, both of which are moving around in large numbers, the occasional Red-breasted Nuthatch, and increasing numbers of Bullock’s Oriole and Lazuli Bunting