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Middle Elevation Riparian Woodland
Description, importance and conservation status:

Middle Elevation Riparian Woodlands are found throughout the state, excluding most of the southwest, from just below 3000 feet in the lower Pecos Valley to 7500 feet or higher in some areas. These habitats are found primarily on the Rio Grande, Pecos, San Juan, Canadian, and Dry Cimmaron Rivers and their tributaries. Other riparian woodlands occur in canyons within the smaller mountain ranges.

This habitat is characterized by tree- and/or shrub-dominated areas along streams, primarily in canyons or valleys associated with permanent water or a consistently high water table. In these canyons, the surrounding upland vegetation consists of oak/pinyon-juniper and ponderosa pine (Pinus ponderosa). In valleys, the uplands are grasslands or shrublands. Middle Elevation Riparian woodlands are generally dominated by Fremont cottonwood (Populus fremontii), or at higher elevations lanceleaf cottonwood (P. acuminata). South of Fort Sumner along the Pecos River and in other river valleys, salt cedar (Tamarix spp.), an exotic species, dominates. Codominants can include peachleaf willow (Salix amygdaloides) in the north and Goodding willow (S. gooddingii) in southern areas. Other trees include Arizona walnut (Juglans major), New Mexico locust (Robinia neomexicana), New Mexico olive (Forestiera neomexicana) and Gambel oak (Quercus gambelii) along with Russian-olive (Elaeagnus angustifolia), another exotic. Shrubs found in these areas include bluestem willow (S. irrorata), coyote willow (S. exigua), southwest rabbitbrush (Chrysothamnus pulchellus), silvery buffaloberry (Shepherdia argentea), wright silktassel (Garrya wrightii) and skunkbush (Rhus trilobata).

Riparian areas are the among the most species-rich habitats in New Mexico. They support a higher percentage of breeding species than other habitats due to their complex structural components and the continual presence of water. Marshes and other wetland habitats are created by widening river valleys or through the creation of oxbows. Additionally, these areas provide water for many species found in adjacent habitats not normally associated with riparian woodland. In Southwestern Riparian Woodland, Stoleson and Finch (1998) have studied breeding bird density in six areas along the New Mexico portion of the Gila River. In these areas, they have documented some of the highest breeding bird densities north of Mexico. While these high densities may not translate exactly to Middle Elevation Riparian Woodland it indicates the importance of riparian habitats to New Mexico birds.

Historically, natural flooding maintained the dynamic nature to which this habitat is adapted. Currently, flooding regimes in this habitat have been drastically altered by dams and the draw-off of water for agricultural, industrial, and municipal use.

Gallery forests are important components of woodlands along the Rio Grande and several other rivers, excluding the Pecos River south of Fort Sumner. In these forests, shade-tolerant species replace pioneering species that require more open conditions. There is more available moisture in these forests as a result of reduced soil temperatures beneath the canopy. Mature forests resist flooding, resulting in reduced erosion and bank containment, except in extreme cases (Dick-Peddie 1993).

Brown-headed Cowbird parasitism may be an increasing problem. Mehlman (1995) documents elevated cowbird numbers, concurrent with broadening distribution, based upon New Mexico BBS routes from 1968 to 1994. During that period, cowbird occurence increased from 50% to 90% of New Mexico routes. Average cowbird numbers have increased by almost 100% since 1968. Mehlman notes that these birds may already have a substantial impact on populations of species like Willow Flycatcher, Bell’s Vireo, and Yellow Warbler. Parasitism is a symptom of overall habitat changes, and not the ultimate cause of population declines. However, with the advent of cattle grazing in the southwest, regular feeding stations in an area allow the constant presence of cowbirds which have been documented traveling up to 12 miles (20km) or more, from foraging areas in search of nests to parasitize (Goguen and Mathews 1997).

Impacts to habitat include: 1) habitat reduction through development or for agriculture, 2) overgrazing 3) off-road vehicle use, 4) lack of cottonwood and willow regeneration due to altered flow/flood regimes, 5) lowered water tables, 6) water diversion or damming, 7) poor instream flow management , and 8) fire (a significant threat in the middle Rio Grande Valley).

Managers of these lands include the Army Corps of Engineers, Bureau of Land Management, National Park Service, Bureau of Reclamation, U.S. Forest Service, U.S. Fish and Wildlife Service, Pueblo and other tribal governments, the state, private land-owners and a few Spanish land-grant holders.

Physiographic Areas covered: Chihuahuan Desert, Mogollon Rim, Colorado Plateau, Pecos and Staked Plains, and the Southern Rockies.

Associated priority species from Appendices B and C:

Table 1. Middle Elevation Riparian Woodland Priority Species
TR>

Highest Priority	Priority	High Responsibility
Yellow-billed Cuckoo Lewis’s Woodpecker Red-headed Woodpecker Willow Flycatcher Lucy’s Warbler Summer Tanager Painted Bunting	Wood Duck Mississippi Kite Common Black-Hawk Gambel’s Quail Eastern Phoebe Bell’s Vireo Plumbeous Vireo Eastern Bluebird Brown Thrasher Orchard Oriole	Greater Roadrunner Black-chinned Hummingbird Ladder-backed Woodpecker Western Wood-Pewee Cassin’s Kingbird Violet-green Swallow
Additional Representative Species: Gray Catbird

Bird Habitat Requirements, Population and/or Habitat Objectives:
(in taxonomic order)

Yellow-billed Cuckoo _{(Yanishevsky and Petring-Rupp 1997)}

Associated Species: Cooper’s Hawk, Red-headed Woodpecker, Brown-crested Flycatcher, Yellow Warbler, Summer Tanager, Indigo Bunting, Painted Bunting, Bullock’s Oriole

riparian obligate preferring later seral stages of cottonwood/willow associations with a dense understory
nests in tamarisk when native vegetation not available in the Pecos Valley, not elsewhere (Howe 1986)
density along the Pecos is positively correlated with height of tamarisk (B. Howe pers.comm.)
along the Gila, breeding is confined to the tallest, densest patches (Stoleson and Finch 1998)
prefers standing or slow-moving water within 328 ft (100m)
sensitive to fragmentation and patches of 99ac (40ha) minimum in many areas; occupy much smaller patches on the Gila:sometimes as little as 7ac (3ha) with short distances 164-1640 ft (50-500m) between patches. (S. Stoleson pers.comm.)
along the Gila River, nest heights range from 8.9-61.7 ft (2.7 -18.8m) averaging 30.5 ft (9.3m) in deciduous trees (S. Stoleson pers. comm.) often overgrown with vines and well concealed by surrounding or overhanging foliage
breeding often coincides with cicada or tent caterpillar outbreaks
hairy caterpillars comprise a large proportion of diet

Distribution: Found statewide in riparian areas and walnut-lined corridors, but less common in the far northwestern and far northeastern portions of the state.

Population and/or Habitat Objectives:

in Region 2, T = -1.6%, p = 0.001, N =200, RA=6.35 (Sauer et al. 1997)
maintain habitat or enhance more cottonwood/willow associations where appropriate along the lower Pecos River (Fort Sumner south) and Middle Rio Grande Valley (Espanola to La Joya excluding urbanized areas) to maintain species density at 3pair per 100ac (Howe 1986)
maintain density at 1pair per 100ac along the San Juan River and in urbanized stretches in the Middle Rio Grande Valley (Howe 1986)
protect current cuckoo nesting areas
regenerate potential cuckoo habitat near existing habitat using not only cottonwood but willow pole plantings
graze riparian areas that meet habitat requirements lightly or in ways which do not destroy the density of the understory
maintain a minimum 20ft (65.6 m) height in dominant trees. Well developed low- and mid-story are essential to maintain a high density of birds
encourage any and all native revegetation efforts below Caballo Dam on the Rio Grande

Lewis’s Woodpecker_{(Tobalske 1997)}

Associated species: Western Screech-Owl, Black-chinned Hummingbird, Western Wood-Pewee, Eastern Phoebe, Cassin’s Kingbird, Black-capped Chickadee, White-breasted Nuthatch, Summer Tanager

a very large open canopy, and standing dead or downed snags are important for perches and food sources
found in three distinct habitats: open cottonwood-dominated riparian woodland, but also open ponderosa pine forest and burned pine forest. May also use old orchards and semi-urban areas
pine forests may be preferred at higher elevations; cottonwood forests are preferred at lower elevations
in burned forest, may move in several years after a fire
nests in large, dead or decaying trees often just before a branching limb
nest trees are larger and taller than random sample
often exhibits semi-colonial nature

Distribution: found in mountainous areas from the Sacramento and Mogollon Mountains north and in lower riparian areas from Belen north.

Population and/or Habitat Objectives:

in the West, T = -1.9%, p = 0.32, N =65, RA=0.18 (Sauer et al. 1997)
monitoring populations may be difficult due to a minimum of nest-site fidelity
maintain known populations south of Cochiti Lake especially in the Corrales Bosque and along the Rio Grande between Isleta Pueblo and Belen
reverse BBS trend to positive significant trend
maintain old, mature cottonwoods and snags where possible and allow regeneration of young cottonwoods

Red-headed Woodpecker _{(Yanishevsky and Petring-Rupp 1997)}

Associated Species: American Kestrel, Northern Flicker, Blue Jay, Eastern Bluebird

riparian forests; also agricultural areas with large trees; may use utility poles
territory size in the eastern U.S. is reported as 10ac (4ha)
may select old burn areas
nest sites generally surrounded by 98ft (30m) of open areas that contain dead or live trees
in Colorado, cottonwoods with the most dead limb length are selected
prefers limbs without bark for nests
excavates cavities where natural crevices exist, generally 10-50 ft (3-18m) above the ground
European Starlings outcompete for nest sites; may be outcompeted by Lewis’s Woodpecker

Distribution: Breeds in the eastern plains, west to Maxwell, possibly Las Vegas, and the Pecos Valley from Fort Sumner south.

Population and/or Habitat Objectives:

in Region 2, T = -4.3%, p = 0.001, N = 87, RA=0.82 (Sauer et al. 1997)
maintain at least 30 breeding pairs in the Fort Sumner area
maintain populations of at least 8 breeding pair at Bosque Grande (Chaves County), Boone’s Draw, Tucumcari area, and Corrumpa Creek (Union County)
increase other breeding populations in the Pecos and Staked Plains and eastern Colorado Plateau
encourage continual regeneration or pole planting of cottonwoods to keep established populations as older nest trees become unusable in the future
maintain dead limbs or limit their removal
protect snags in groups
maintain a range of tree heights and diameters within known breeding areas
avoid activities that encourage European Starlings
preserve habitat blocks of greater than 10ac (4ha)

Southwestern Willow Flycatcher _{(Stoleson and Finch 1998)}

Associated Species: Green Heron, Bell’s Vireo, Gray Catbird, Yellow Warbler, Yellow-breasted Chat, Blue Grosbeak

riparian obligate needing dense habitat and wet soil (NM PIF)
often found on broad, floodplain areas; avoids narrow and steep-sided canyons
10-33 ft (3-10m) tall willows, especially mid-successional stages of willows with coyote willow or other dense shrub understory offering multi-layered structure, is very important (NM PIF)
Willows are the preferred nesting substrate throughout New Mexico. The exceptions are: nesting in boxelders along the Gila River and tamarisk nesting on the Rio Grande
mean nest height on the Gila is 24.3 ft (7.4m); much lower in the rest of the state (NM PIF)
preliminary analyses of microhabitat along the Gila indicates preference for open water or saturated soils, high stem densities, dense understory, dense foliage structure, high canopy cover, and presence of willows; outside of the high canopy cover other habitat variables are consistent with the rest of the state
predation is a larger problem in the north than further south
will nest in tamarisk and Russian-olive to varying degrees with appropriate understory structure

Distribution: Core population for the United States in along the Gila River. Other populations scattered across the state but only one current nesting site east of the Rockies.

Population and/or Habitat Objectives:

No BBS data available for this subspecies
establish 3 disjunct populations of at least 12 breeding pair in the state by 2009
establish 2 populations of lesser numbers near each core breeding area
manage potential habitat to achieve structural and vegetation characteristics necessary to support increasing numbers of breeding Flycatchers within 20 years
establish or maintain 6 disjunct populations of at least 12 breeding pairs each with 2 satellite populations of lesser numbers by 2019
maintain dense multi-storied riparian habitat
maintain mature boxelders on the Gila River. In general, extremely dense, tall 10-33 ft (3-10m) willows or other shrubs are required for nesting. Nesting in taller boxelder occurs on this river. On the Gila River, work will also benefit this species as long a multi-story habitat with willow presence is maintained
manage water levels to maintain soil saturation in appropriate habitat
tamarisk eradication is not necessarily part of managing for this species, however when paired with cottonwood and willow reintroduction the habitat eventually produced is considered more suitable

Gray Catbird _{(Cimprich and Moore 1995)}

Associated Species: Green Heron, Yellow Warbler, Yellow-breasted Chat, Song Sparrow, Black-headed Grosbeak, Blue Grosbeak, Lazuli Bunting, Bullock’s Oriole, Lesser Goldfinch

New Mexico, closely tied to streams and/or irrigation ditches with dense shrubs (NMPIF)
uses extremely dense thickets of shrubs, willow or alder; Catbird density increases with shrub/tree density
nests near main trunk of plant in dense shrubbery; average height of nest is generally 56.9% of nest plant height; average height of support tree is 7.5 ft (2.5m)
most frequently uses horizontal supporting branches averaging 0.51 in (1.3cm) in diameter

Distribution: Breeds in the Rio Grande Valley from Bosque del Apache NWR north, and from Las Vegas north. Recently also found along the San Juan River and along the Rio Grande near Radium Springs.

Population and/or Habitat Objectives:

in Region 2, T = 0.4%, p = 0.93, N = 25, RA=0.10 (Sauer et al. 1997)
maintain dense streamside thickets of shrubs, generally willow or alder; density is positively correlated with shrub/tree density

Lucy's Warbler _{(Stoleson et al. 2000)}

Associated Species: Yellow-billed Cuckoo, Summer Tanager, Black-headed Grosbeak, Blue Grosbeak, Bullock's Oriole

mature closed-canopy riparian bosque and late successional stage woodlands, (Stoleson 1998) up to approximately 5000 ft in elevation (T. Corman pers.comm.)
nests in cavities or behind loose bark, burrows or depressions in banks or rocky crevices, may use tamarisk if all that is available. Will occasionally nest in deserted Verdin or Toxostoma thrasher spp. cavities
nests in New Mexico have been found in cottonwood, Goodding willow and boxelder; in Arizona where the species has been more extensively studied, the species nests primarily in tall, dense mesquite. This has not been documented in New Mexico
nests in New Mexico range from 3-43 ft (0.9 - 13.2m) above ground with mean height of 23 ft (7.1m)
will not use nest boxes

Distribution: Found in the southwestern quadrant of the state north in the Rio Grande Valley to Socorro and occasionally to Bernardo and in the west north to Glenwood area. Not found further east than the Rio Grande River.

Population and/or Habitat Objectives:

in Region 2, T = -0.3%, p = 0.8, N = 35, RA=8.22 (Sauer et al. 1997)
maintain or enhance suitable habitat to establish 8 pair per mile in the Rio Grande watershed from Socorro south
maintain closed canopy riparian forest
maintain snags along streamsides
reduce the use of levees to allow floodplain use by rivers during highflow events

Summer Tanager_{(Robinson 1996)}

Associated Species: Black-crowned Night-Heron, Cooper’s Hawk, Common Black-Hawk, Lewis’s Woodpecker, Lucy’s Warbler, Yellow Warbler, Blue Grosbeak

occupies riparian woodlands dominated by tall cottonwood, willow, and sycamore where they occur (NM PIF)
uses cottonwood, Goodding willow and boxelder for nesting in New Mexico (S. Stoleson pers.comm.)
May use tamarisk dominated woodland at higher elevations (up to approx. 5500ft); tamarisk must be at least 20 ft (66m) in height (B. Howe pers. comm.)
nests on the Gila River ranged from 14-98 ft (4.3-30m) averaging 39.7 ft (12.1m in height) (Stoleson and Finch 1998)
bee and wasp specialist; also takes other flying insects; will eat fruit in fall
forages at average heights of approx. 31 ft (10m) in trees depending on forest structure
in CA, average height of nests was 35ft (11.3m)

Distribution: Found in drainages in most of the southern two thirds of the state north to Cochiti, probably also regular in small numbers in the Canadian River drainage south of Mills Canyon.

Population and/or Habitat Objectives:

in Region 2, T = -0.05%, p = 0.37, N = 115, RA=1.44 (Sauer et al. 1997)
maintain a density of 10 pair per mile along the Rio Grande from Cochiti Lake to Bosque del Apache NWR (Hink & Ohmart 1985), 2 pair per mile along the Pecos River from Santa Rosa south in appropriate habitat (Howe 1986)
enhance habitat to create conditions favorable to the reestablishment of populations in at least one site above Cochiti Lake
maintain mature riparian forests with cottonwood and willow associations
maintain riparian tree height at 20ft (66m), preferably higher

Painted Bunting _{(Lowther et al. 1999)}

Associated Species: Northern Bobwhite, Yellow-billed Cuckoo, Western Kingbird, Northern Cardinal, Blue Grosbeak, Common Grackle

open areas with large trees or shrubs, sometimes near water, especially streamsides
in TX, somewhat open areas with scattered shrubs, or streamside bushes with patches of grass or weeds, becoming less abundant with increased or decreased tree density (Oberholser 1974 in Lowther et al. 1999)
in southeastern NM, often nests in mesquite grassland and desert shrubs such as hackberry; in central-eastern NM, uses dense shelter belts and hedgerows adjacent to open fields and mesquite grasslands (NMPIF)
nests in deep cups attached to twigs from 3-48 ft (0.9 - 15m) above ground averaging 3.5ft (1.14m) above ground in TX (Barber and Martin 1997 in Lowther et al. 1999)
susceptible to cowbird parasitism
may raise two or more broods a year

Distribution: Found in the Pecos Valley north to Carlsbad, occasionally in Roswell and the Rio Grande Valley north to Hatch; also a small population in the Tucumcari area.

Population and/or Habitat Objectives:

in Region 2, T = -3.2%, p = 0.00, N = 189, RA = 10.21 (Sauer et al. 1997)
increase population at Rattlesnake Springs to pre-1988 levels: 8 breeding pairs
increase to 5 populations in the Chihuahuan Desert and 2 in the Pecos and Staked Plains
maintain presence at recently discovered sites in the Chihuahuan Desert

Overall Habitat Strategies:

Whenever possible, it is recommended that conservation easements be obtained on lands with riparian areas. It is also suggested that riparian lands be purchased from willing sellers.

Grazing - Non-growing season, short duration, or rest-rotation grazing and appropriate stocking rates allow for the establishment of appropriate riparian habitats. It is also recommended that upland water sources be provided for cattle, away from riparian areas, rather than using streams for watering

Fire - Restore cottonwood and willow saplings as soon as possible after fire in riparian areas.

Water - Restore natural flood cycles or adjust water flow to emulate regular flood cycles, at least every 5 years, in conjunction with cottonwood and willow establishment, if natural regeneration does not occur.

Tamarisk control - Control tamarisk where appropriate, especially along the Middle and Lower Rio Grande, concurrent with cottonwood and willow replanting. NOTE: tamarisk removal without concurrent native reseeding efforts is not recommended.

Research and monitoring needs:

1. Determine nesting success of Yellow-billed Cuckoo in tamarisk versus well-developed cottonwood/willow riparian systems. Determine Yellow-billed Cuckoo populations for the state.

2. Determine feasibility of reestablishing Red-headed Woodpecker breeding areas at Maxwell, Las Vegas, and the Rio Grande Valley.

3. Survey for Summer Tanager nesting pairs along the Canadian River.

4. Determine nesting success required to sustain a viable population of Painted Buntings. Survey for nesting pairs in the Tucumcari area and additional sites.

5. Determine effects of differing grazing regimes in riparian areas using scientifically rigorous, and statistically robust studies.

6. Determine potential role of corvid populations on other bird populations in riparian areas, especially in the northern half of the state.

Additional species for which monitoring is recommended:

Table 2. Middle Elevation Riparian Woodland Priority Species: Habitat Factors

Species	Vegetation Composition/ Structure	Abiotic Factors	Landscape Factors	Special Factors
YBCU	later seral stages of cottonwood/willow associations with dense understory		minimum of 198ac patches are preferable	extremely sensitive to fragmentation
LEWO	cottonwood riparian, ponderosa pine and burned pine areas; can use old orchards or semi-urban areas; open canopy with snags	pine forests preferred at higher elevations, cottonwood at lower elev.
RHWO	cottonwood riparian areas; nest limbs are stripped of bark; trees with the most dead limbs are selected for nesting in CO	nest trees have approx. 98ft surrounding open space with live or dead snags	territory size reported to be 10ac in East
WIFL	willow associated riparian areas; dense multi-storied understory; 10-33ft willows for nesting	saturated soil or slow-moving water adjacent to nesting area	often found on broad, floodplains; avoids narrow and steep-sided canyons
GRCA	shrubs often large willow or alder creating dense understory		closely tied to streams or very wet areas in NM	density of birds increases with density of understory
LUWA	mature, closed canopy cottonwood forest	trees must be large enough to have loose bark or support woodpecker cavities		will not use nest boxes
SUTA	cottonwood/willow forests with trees at least 35 ft; may use tamarisk at higher elevations but must be at least 20 ft.			bee and wasp specialist
PABU	open areas adjacent to somewhat dense trees or shrubs		nests can be associated with water	susceptible to cowbird parasitism