Hawks Aloft Inc.
PO Box 10028
Albuquerque, NM 87184
Phone: 505 828-9455
Fax: 505 828-9769
E-Mail: gail@hawksaloft.org

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Hawks Aloft Blog

Falcon Facts

One of our annual fundraisers is a photo shoot and lecture of some of our educational ambassadors and the wild cousins they represent.  We thank Doug Brown, Keith Bauer and Greg Basco for organizing this as a part of one of their multi-day photography workshops.  You might also note that many of the images that you see on our website and Facebook pages, are donated to us by these superb photographers.  This year, we thought it would be fun to take all four species of falcon that might be found in this region at some time of the year to the class.

Male American Kestrel.  Image by Keith Bauer.

Male American Kestrel. Image by David Powell.

The American Kestrel, represented here by our avian  ambassador, Clark Kent, is the smallest falcon in North America.  In New Mexico, it is present year-round.  One of the fascinating facts about this particular species is that males and females have markedly different plumage.  Clark Kent was named by one of our youngest volunteers, Lindsey Porter.  When given the task, she was told the name must be educational.  “Clark Kent” was named as the alter ego of Superman because Lindsey learned to tell the difference in the sexes when told that “each morning when the boys get up they don their blue Superman cape”, just like the action figure. Females are brown and black barred throughout, except for a circle of blue-gray on their heads.

Meet our newest Educational Ambassador, Merlie, a female Merlin.  Image by Keith Bauer.

Meet our newest Educational Ambassador, Merlie, a female Merlin. Image by Keith Bauer.

Merlins are somewhat larger and definitely heftier than the diminutive kestrels.  In New Mexico, they are present only during the winter months.  They nest in the boreal forest of the northern U.S. and Canada.  “Merlie Falconbird” was named by Will Fetz, six-year-old son of Trevor Fetz, our lead avian biologist.  Will was adamant that Merlie have both a first and last name.  At first glance, Merlins look like a weird female kestrel with the vertically streaked breast and pale malar stripes.  But upon closer inspection, Merlins have banded tails and are stockier than kestrels.  They also have different plumages between males and females but the differences are less obvious. You can tell that Merlie is a juvenile by the bluish membranes around her eyes and nares.

Sunny, the Prairie Falcon.  Image by Keith Bauer.

Sunny, the Prairie Falcon. Image by Keith Bauer.

Prairie Falcons are the large falcon of the arid West.  They are found in drier habitats than their similar sized cousin the Peregrine Falcon, nesting on rock faces and preying primarily on other birds captured after a low coursing flight over uneven terrain.  The Prairie Falcon is brown on the back and whitish and brown on the breast.  “Sunny” was named by Gena Esposito, our education and outreach coordinator in 2013, when he was admitted with his wingtip shorn away.  He was found on a trail by hikers, far from any roads, so we have no idea how he was injured.  He was named Sunny after Butch Cassidy, the Sundance Kid, for his plucky, survival instincts and the dark malar stripe that reminded her of the moustache of the Sundance Kid.  In this image, you can see that Sunny is undergoing a molt.  The darker feathers are the new ones that are growing in, while the pale feathers are the worn ones that are being replaced.

Isis, the Peregrine Falcon.  Image by Keith Bauer.

Isis, the Peregrine Falcon. Image by Keith Bauer.

Isis represents the goddess of the same name, the most powerful of all.  The Peregrine Falcon is the largest falcon in this area, eclipsed only by the Gyrfalcon of the Arctic Regions.  In New Mexico, peregrines nest on tall cliffs, usually near water.  They have been documented by National Geographic diving on prey at speeds of up to 248 MPH.    This makes them the fastest flying birds in the world, in a stoop.   Their prey is generally other birds that they capture in the air.  Isis is an adult peregrine, evidenced by her full black hood.  All falcons have dark eyes.

 

 

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Bioaccumulation: A Lesson from the Peregrine Falcon

Peregrine Falcon

Peregrine Falcon. Image by David Powell.

Bioaccumulation is the process in which the toxins in the environment are collected little by little by the organisms at the bottom of the food chain (i.e. plants, plant eating animals). As the toxin accumulates in the bodies of larger predators, it can reach lethal dosages within individuals. The top predators, those that never directly ingested the toxins, are affected by the indirect consumption of poisoned prey.

The story of DDT is popular with this theme in our elementary school programs.  Our educational Peregrine Falcon is often used for this lesson. Most students have never heard of DDT or about the endangerment of Peregrine Falcons,  Bald Eagles, and the Osprey (or fish hawk).  To demonstrate the bioaccumulation topic to today’s children, we play the bioaccumulation game.

This game is played in multiple stages. It starts with a rectangular area to represent a farm field (about 15 by 10 feet), and a student designated as a farmer. The farmer is responsible for spreading the nutrients needed to grow his crops; the nutrients are represented by poker chips of varying colors (about 50 chips). The rest of the students are asked, “What are the nutrients needed by plants (e.g. water, sunlight, fertilizer)?”

Then, about half of the students are given small plastic cups to represent their stomachs. These students are the ‘grasshoppers’ that eat the farmer’s plants, and nutrients for the plants. The farmer steps aside, and the grasshoppers

Peregrine Falcon with chicks.  Image courtesy of the US Fish and Wildlife Service.

Peregrine Falcon with chicks. Image courtesy of the US Fish and Wildlife Service.

pick up, or “eat”, the poker chip nutrients.  When all of the poker chips are collected, the grasshoppers step outside the farm field and count how many red colored chips they have acquired. Students have to remember their number, and the grasshoppers return to the inside of the field. A smaller group of students are given larger cups, to represent their ‘sparrow stomach’.  The grasshoppers are then preyed upon by the sparrows. The grasshoppers hop around to avoid being tagged by the walking sparrows. Once tagged, the grasshoppers empty the contents of their stomach into the sparrow’s stomach, and hop outside the field. Once all of the grasshoppers are eaten, the sparrows count how many red chips they have in their stomachs. The sparrow students step back into the field, and 2-3 students, representing the falcons, are given the largest cups. The falcons can run around the field, while the sparrows can only walk, trying to avoid getting eaten.  When all of the sparrows have been eaten, the falcons count how many red chips they accumulated in their stomachs.

At this time, we all gather to discuss what was really going on. The farmer is called back up, and is asked what he/she planted in the field. Do you want the grasshoppers to eat all your crops?  What do you do to keep them away? The students easily answer, “Use poison!” At this point, I share with the students that the red poker chip they collected was the poison.  If they had more than 10 chips, then they were poisoned and died. And, all of the falcons should have collected more than 10 red chips!

We then talk about how many animals survived with a little poison, but that all of the falcons died with lots of poison. I ask students if they think this really could have happened, and they all agree that it probably did.  From there, we ask students what they think we could do to stop grasshoppers from eating crops and what could be done to help falcons. The students come up with all types of answers, from more sparrows that eat the grasshoppers, to catching all the grasshoppers and feeding it to our kestrels.  

BAEA Juvie taking off - 10-13

Bald Eagles are now protected from DDT, but lead poisoning through fishing sinkers and lead bullets is an on going bioaccumulation threat. Image by Doug Brown

 

 

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The Desert in Winter

The Journada del Muerto in Winter

The Journada del Muerto in Winter

Twenty years ago, we began doing raptor surveys of the Rio Grande and Estancia Valleys, monitoring during the months that raptors are resident, summer and winter.  I am fortunate to survey the desert grasslands of the Armendaris Ranch, owned by Ted Turner.  It’s one of the largest privately owned ranches in New Mexico and stewardship of the fragile environment is a priority.

Bison

Bison

They raise bison on the expansive ranch, but mostly there is little evidence that this land is grazed by anything other than wildlife.

Golden Winter Grasses that Frame the Fra Cristobals

Golden Winter Grasses that Frame the Fra Cristobals

The grasses are tall and golden at this time of the year, as well as abundant.  In many areas on the ranch, you could fool yourself that you were in a pristine environment, except for the road, of course.  Along with my survey partner, Chuck Brandt, we survey a 20 mile stretch of the ranch on the main ranch road.

Chuck Scans for Raptors

Chuck Scans for Raptors

At each of 20 stops, we scan 360 degrees in search of raptors, Loggerhead Shrikes, and Greater Roadrunners.  With the high pressure system riding high over the West, the temperatures last week were positively balmy with relatively light winds.

Playa at the Armendaris Ranch, a full month after the last precipitation.

Playa at the Armendaris Ranch, a full month after the last precipitation.

We haven’t had any rain in nearly 40 days, but when it does rain in the desert, it can be substantial.  Such was the case in late November, when the ranch received significant snow that closed the main ranch road and filled the playas.  Now, in mid-January, the playas still held bounteous water.

Chihuahuan Raven Kettle

Chihuahuan Raven Kettle

Chihuahuan Ravens were in abundance as we arrived, riding the winds in multiple kettles of up to 50 birds.  Chuck commented that, in his experience, the presence of loads of ravens boded poorly for raptor numbers.  But, to our surprise, we started off with at least one bird at every early stop.  But . . .

Loggerhead Shrike, image by Doug Brown

Loggerhead Shrike, image by Doug Brown

most of them were Loggerhead Shrikes, also known as butcherbirds, for their hunting habits.  They capture live prey and impale it on thorns and barbs to be consumed later.  In all, we tallied 12 Loggerhead Shrikes on this survey.

Lark Buntings on Armendaris

Lark Buntings on Armendaris

Also present were Lark Buntings, seen in huge flocks of a hundred or more.  Watching these flocks with their unique flight styles foraging on the roads and nearby shrubs is thrilling as they undulate in almost coordinated flight.  Of course, the other songbird present in large numbers was the Horned Lark.

Immature Golden Eagle

Immature Golden Eagle

But, the highlight of the day was sighting three individual Golden Eagles, not a common sight, so seeing three in one day was thrilling, even though the birds were distant.  We also counted Prairie Falcon, American Kestrel, Red-tailed Hawk, and Ferruginous Hawk.  It is clear that the management practices of the Armendaris Ranch benefit raptors and their prey!

Yucca in Winter

Yucca in Winter

Some folks have difficulty in finding much to appreciate in the desert at any time of year but, for me, it bespeaks unsurpassed beauty in nature.

 

 

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Hawks Aloft Volunteers to the Rescue

Davedda Thomas and her Precious Cargo

Davedda Thomas and her Precious Cargo

One thing’s for sure at the Hawks Aloft office — Life is never dull!  Thanks to our Raptor Rescue Team, we never know what will come our way.  This week, Davedda and Tony Thomas volunteered to drive to Vaughn, New Mexico to transport birds to Albuquerque.  The birds were coming up from Desert Willow Animal Clinic where Dr. Samantha Rayroux takes in injured birds in that part of the state.  We put the call for help out on e-mail, and Davedda called right back!  It’s a 2+ hour drive one way to get to Vaughn, plus the return! So, it was mid-afternoon when they showed up with their precious load of cargo.

Two of the boxes held one bird each: a Great Horned Owl and a Merlin (a small falcon).  Lori Paras from the Santa Fe Raptor Center was on hand to take them the remainder of their journey to her facility, the Santa Fe Raptor Center for care.  That left one box, destined for Wildlife Rescue of New Mexico, a local wildlife rehabilitation organization, containing an educational Chihuahuan Raven also known as the white-necked raven.  Look carefully at the boxes – one of them is not like the others.

Peeking Out

Peeking Out

Seems the young lady had been pounding away on the five hour journey up from Carlsbad and had worn a small hole in the box top.  With a little extra lift,

Help Let me out of here!

Help Let me out of here!

she got her first look at us.  The female raven was illegally held by a family in the Carlsbad area, where she lived in their house with free reign, and liked to eat pizza.  An obvious imprint, this was not a good start for a bird that should have been wild.  She will become the newest member of the Wildlife Rescue educational ambassadors.  Lisa Morgan, our Raptor Rescue Coordinator and I had offered to put her equipment on, the bracelets and leather straps that all education birds wear.  So, we opened the box a little wider and

Ebony

Ebony, so named by the Desert Willow Staff

she made herself right at home in the office.  We enjoyed her company for a couple of hours and what a treat it was!  It was hard to hand this charmer of a bird over to her new caretaker, Jim Battaglia.  We hope to keep visiting rights.

Ebony from Carlsbad

Ebony, from Carlsbad

Although she might be physically perfect, imprinting is irreversible as the animal does not recognize its own species, and thinks that it is like those that raised it.

 

 

 

 

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Thievery – A Perfectly Reasonable Way to Get Food

We received this image from Doug Brown this week.  Doug  reports that he had a special encounter with an American Kestrel.   He and fellow photographer, David Salem, used their vehicle as a blind to reduce disturbance.  Here’s the rest of their story.Kestrel pic“We were photographing the Kestrel on a perch, when all of a sudden a Sharp-shinned Hawk flew by carrying a Savannah Sparrow.  The Kestrel gave chase and caught the Sharpie.  They locked talons and went spiraling downwards behind a small mound of earth.  The Kestrel reappeared with the Sharpie’s meal and proceeded to land on one of our perches and devour the bird.  What a cool thing to witness!”

Routine behavior for one of the smallest raptors on the planet!  Just last week, I read about a European Kestrel attacking a much larger Barn Owl in an attempt to snare a free meal.  The story includes some amazing action shots of the two birds with locked talons.  Ultimately, the Barn Owl was able to keep its respectably obtained meal.

Northern Harriers Fight over a Meal.  Image by Doug Brown.

Northern Harriers Fight over a Meal. Image by Doug Brown.

We are taught that raptors catch and kill their prey.  However, no raptor is above scavenging a free meal – often the reason why so many hawks, falcons and owls are struck by vehicles as they scavenge for roadkill.  The Northerrn Harrier is a raptor that generally eats small mammals, with a unique hunting style of flying low over fields and marshes with tall grasses, listening as well as looking for the small prey items.  They are not known to catch fish! Above, the juvenile has obviously found a dead fish, a great prize, and the adult female clearly intends to steal it from him/her.

Adult and Juvenile Bald Eagles Squabble.  image by Doug Brown.

Adult and Juvenile Bald Eagles Squabble. image by Doug Brown.

Even among our national symbol, the Bald Eagle, thievery is common.  Here, an adult attacks a youngster that has a chunk of fish in his foot.

It is rare, however, to capture images of this behavior in action.  We thank Doug Brown and our many photographers who contribute their work to us!

 

 

 

 

 

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The HAI Flier – Our Monthly Online Newsletter

Sandhill Crane in Flight.  Image by Doug Brown.

Sandhill Crane in Flight. Image by Doug Brown.

Sandhill Cranes will be returning to the Middle Rio Grande Valley any day now.  Did you know that the Rio Grande and the adjacent bosque have become de facto refugia for these magnificent birds because no hunting is allowed within the urban areas.   Read about this issue and more in the October issue of the HAI Flier.   It is your way to keep in touch with all of the studies and education programs of Hawks Aloft, and membership activities too.

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Steller’s Jays on the Move

Steller's Jay.  Image by David Powell

Steller’s Jay. Image by David Powell

Steller’s Jays are usually  birds of evergreen forests in the mountainous West, including New Mexico.  A common species, they can be found in wilderness, but also are regular attendees of campgrounds, parks, and backyards, where they are quick to spy bird feeders as well as unattended picnic items.

A generalist omnivore, like other corvids, the diet of a  Steller’s Jay includes insects, seeds, berries, nuts, small animals, eggs, and nestlings.  They also are known to consume garbage, unguarded picnic items, and feeder fare such as peanuts, sunflower seeds, and suet.  Steller’s Jays sometimes carry several nuts at a time in their mouth and throat, then bury them one by one as a winter food store.  Studies have shown that these intelligent birds can relocate their cached food items during lean food months.

Steller's Jay.  Image by David Powell.

Steller’s Jay. Image by David Powell.

But, when natural foods are scarce, such as during a drough, like the one that has occurred in New Mexico mountains this past year, they sometimes move, to lower elevations in search of sustenance.  An occasional movement of a species beyond its normal range in response to weather, or food supplies is called an irruption.  As I write this, we are receiving nearly daily reports of Steller’s Jays showing up in the Middle Rio Grande Valley, and in backyards throughout Albuquerque, considerably lower than their normal coniferous forest range.

Steller's Jay.  Image by Doug Brown.

Steller’s Jay. Image by Doug Brown.

These fascinating birds are hardy survivors!  Learn more about them on the Cornell All About Birds website, including their calls.

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Fall Raptor Migration is in Full Swing

We’ve been getting calls this week about large flocks of hawks soaring overhead over the river, the bosque and the Middle Rio Grande valley. They are Swainson’s Hawks that migrate in large groups called ‘kettles’. They have the longest migration of any North American hawk, traveling all the way to Argentina, where they are called Locust Hawks.

Juvenile Swainson's Hawk, photo by David Powell

Juvenile Swainson’s Hawk, photo by David Powell

Their bodies are streamlined and they have long, slim wings — a bird built for long-distance flight.   Juvenile Swainson’s Hawks leave on migration before their parents. Traveling in large kettles helps young ones learn the way. By the time they reach Central America, as many as 100,000 have been seen soaring together at one time.

Kettle of Swainson's Hawk.  Photo be Georgia Santa-Maria.

Kettle of Swainson’s Hawk. Photo be Georgia Santa-Maria.

Swainson’s Hawk are distinctive. They are the only N.A. hawk that has dark flight feathers and a light leading edge to the wing. Watch for them soaring high above the Middle Rio Grande Valley this week, and also in eastern New Mexico, and Texas. Their migration will take up to two months each way.  It’s a 7,000 mile, one-way journey.

Adult Swainson's Hawks soar together.  Photo be Georgia Santa-Maria

Adult Swainson’s Hawks soar together. Photo be Georgia Santa-Maria

Keep an eye out for many raptors soaring overehead, on their way south to their wintering grounds.

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Is the Decline in Avian Density in the Rio Rancho Willow Creek Bosque a Function of Drought?

Hawks Aloft has conducted avian monitoring in the Middle Rio Grande Bosque since 2004.  We monitor 78 transects in a variety of vegetation communities among several management entities.  Each half mile route is surveyed three times per month during the summer and winter months only.

In our blog post of last week, we addressed our concerns with the City of Albuquerque’s Rio Grande Vision Plan (RGV).   Included in that post was a graph that displayed the change in avian density relative to the development of the Rio Rancho bosque in a manner similar to what appears to be envisioned in the RGV.

On the river

At the public meeting, Chuck Buxbaum, environmental science teacher at Sandia Preparatory School, commented that our graph might show the decline in birds relative to the drought, rather than development.   What an excellent question/comment!

In response, we took a look at all of our data and developed the graphs below.  The first graph below shows change in avian density (2004-2012) during the summer months in all vegetation communities combined in Rio Rancho relative to all other survey areas combined.

Overal Density Comparison

The graph above clearly shows a dip in avian density among all areas during the drought years of 2010-2012.  However, across “All Other” areas studied, the decrease in the number of birds per 100 acres did not statistically change between 2010-2012.  There was a slight increase in 2012 densities.

To further query the data, we then analyzed the 2012 densities by vegetation communities, again comparing Rio Rancho to all other transects with similar vegetation communities.  The Willow Creek section of the Rio Rancho bosque contains three different habitat types:

C-2 Natural = mature stands of cottonwood that averaged at least 12 m in height with a sparse and/or patchy understory.
CW6 = Coyote Willow, Type 6.  Low, relatively sparse herbaceous and/or shrubby vegetation, with most of the foliage less than 1.5 m in height.
OP = Mechanically thinned areas with minimal woody vegetation remaining.

We also included data from the following vegetation community, which historically supports the lowest density of birds.

SC5 = Salt Cedar, dense stands with the majority of foliage occurring between 0 and 6 m.

Density by Vegetation Community

In the graph above, it is evident that the Rio Rancho bosque supports lower densities of birds in each of the vegetation communities.  Additionally, when densities in all vegetation communities are averaged, the Rio Rancho bosque supports lower densities than even monotypic stands of salt cedar.

We suggest that the ongoing decrease in avian density in the Rio Rancho bosque is due to escalating human use, increased presence of dogs, many of which are unleashed, and the continual and complete removal of all non-native vegetation, including Russian olive, and junipers (although juniper is a native species).

Please see the notes below for further information and a timeline of changes that have occurred in the bosque since 2004.  If you have any questions, please contact Gail Garber, executive director, or Trevor Fetz, lead avian biologist.

Notes relevant to the summer data

1) Mean avian density in RR equal to or higher than cumulative from other areas in 2004-2005, prior to initiation of widespread clearing in RR.

2) Drop in 2006-2007 in RR corresponds to clearing of all non-native (and some native) vegetation throughout the Willow Creek bosque. We also initiated NW23 in summer 2006, after it had been completely cleared earlier in the year.

3) No clearing occurred in RR between summer 2007 and summer 2008, allowing substantial re-growth of understory and weedy vegetation (especially RO on NW23).

4) Full-scale thinning/mowing resumed in RR prior to summer 2009. Since that time, we have seen a steady decrease in avian density in RR each successive summer. We believe the gravel loop trail was established after summer 2009.

5) The establishment of the gravel loop trail immediately increased human/canine use and associated disturbance of the Willow Creek bosque, which has increased in subsequent years. Based on our casual documentation of humans/dogs on transects, human use has increased each summer.  The increased human use/disturbance each successive year mirrors the decreased avian use each successive year, and it appears that there is a direct connection.

6) The drought began impacting summer birds in the bosque in 2010. In areas outside RR, summer density decreased substantially from 2009 to 2011, but rebounded slightly in 2012. The 2012 water year was slightly better than the 2011 water year, which seems to correlate with the slightly better density numbers in 2012 relative to 2011. In contrast, RR density has consistently declined each successive summer since 2008. Assuming the drought was the overriding factor in the decrease in RR, we would expect a decrease in density more along the lines of what has been documented in other areas, not the steady, steep decline that has been observed.

7) Thus, our interpretation is that although the drought has definitely impacted avian use in RR, the increased human use due to the development of the loop trail is at least as important a factor as the drought. That would also explain why density in RR has decreased so much more than in any other area.

8) Density by Vegetation Community/Structure (C/S) type in RR for 2012 is lower than would be expected relative to densities for same C/S types in other areas (see table below). To me, this further illustrates the impact of the loop trail/increased disturbance in RR.

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Protect our Bosque from the Proposed Rio Grande Vision Plan

It is not often that we, at Hawks Aloft, take on an activist role in our community.  However, we have relatively recently become familiar with the details of the Rio Grande Vision Plan, proposed by Mayor Berry and his design team.   That site was updated only yesterday, therefore considerable detail has not yet been reviewed.   There is a public meeting tonight

Wednesday Sept. 4, 6 -8 pm

Albuquerque Museum
2000 Mountain NW
Albuquerque NM 87104

There will be a second public meeting on Wednesday Sept. 18, 6 -8 pm.

We encourage you to familiarize yourself with the plan, attend the meetings and express your opinions, either through the public meeting venue or by submitting written comments to via email to theplan@cabq.gov Comments may also be mailed to The Mayor’s Office, PO Box 1293, Albuquerque NM 87103. 

As an organization that cares deeply about the health of our bosque, we mailed a letter to the Mayor on September 3, 2013, the same date as the revised Plan was posted on the City website.  We urged Mayor Berry and his team to consider the effects of a similar management that has occurred in the Rio Rancho bosque over the past 10 years and the devastating impacts to bird densities as that reach of the bosque has become more ubanized.  A full copy of our letter to the Mayor follows below this chart.

Rio Rancho bosque Avian  Densities 2003-2012

Rio Rancho bosque Avian Densities 2003-2012

September 3, 2013

Mayor Richard Berry
City of Albuquerque
PO Box 1293
Albuquerque, NM 87103

Hawks Aloft, Inc. is deeply concerned that the City of Albuquerque’s Rio Grande Vision Plan, if enacted, will have a devastating effect on avifauna and other wildlife that depend on the natural habitat of the bosque. We base our concerns on scientific data collected by Hawks Aloft, Inc. We have conducted avian monitoring within the bosque, between Bernalillo and the La Joya Game Management Area since December 2003. The purpose of our study is to assess avian abundance and species richness (number of different species observed) relative to habitat and management entities. We currently monitor 78 (½ mile long) transects in various habitats. Each route is surveyed three times per month during the summer and winter months, when the birds present are resident, rather than migratory.

As greater detail has been released about the Rio Grande Vision Plan, it is apparent that large portions of the bosque within the Rio Grande Valley State Park will be developed to increase human usage, with hardened riverside trails up to as 8-10’ wide, viewing blinds, benches, and other park-like amenities,  many of which are proposed for installation along the river’s edge.  The Plan also calls for removal of non-native vegetation as part of a restoration process.  All of these sound very similar to the Willow Creek bosque management that has occurred in our neighbor to the north, Rio Rancho.

The Rio Rancho bosque has undergone significant changes, from an unmanaged wild area in 2003 to urban parkland between 2004 and 2012. (Changes have occurred in 2013, but data are still being analyzed).  We have documented a significant decline in avian abundance over time as this section of bosque has become increasingly developed.

We provide the history below as potential explanation for the change in bird densities in the Rio Rancho bosque.

2004-2005:      Mechanical clearing of non-native woody vegetation occurred in some areas. Sunflower crop was poor, resulting in relatively low bird numbers during winter.  Limited human use.

2006-2007:      Vegetation re-growth and presence of extensive sunflower patches. The sunflowers attracted large numbers of wintering birds, especially sparrows and finches.

2008-2009:      Crusher-fine loop trail installed.  Human use began increasing as soon as trail was completed.  No winter surveys conducted due to lack of funds.

2009-2010:      Clearing resumed, again using heavy equipment, resulting in removal of all woody vegetation except for coyote willow, cottonwoods, and a few, scattered New Mexico olives. Expanded wide, crusher-fine, walking trails, and smaller trails with classroom style seating.  Sunflowers were mowed prior to setting seed.

2011-2012:      Avian density among the lowest of all transects surveyed.

2013:               Additional crusher-fine trails and benches installed. Riverbed altered to shift water flow closer to the Rio Rancho bosque and provide benefit to silvery minnow. Fill from riverbed mounded on west edge. Fill area seeded; minimal planting of shrubs.

Human and dog use of the Willow Creek bosque has grown exponentially since the establishment of the wide, crusher-fine trail.  It is not unusual to encounter 20-30 people and up to 10 dogs, many of them off-leash, during a ½ mile long transect. This bosque has become a place for people and a de facto dog park, with little natural habitat for wildlife.  Birds that utilize the shrub understory and ground dwelling species have largely disappeared due to the lack of cover and persecution by unleashed dogs.  Those birds present are largely canopy dwelling species such as White-breasted Nuthatch, Downy Woodpecker, House Finch, and Black-chinned Hummingbird.

All Russian olive (non-native) and junipers (native) have been removed from the Willow Creek bosque. Russian olive is of vital importance to birds in the middle Rio Grande bosque. It is, in general, greatly undervalued by land managers, but provides important nesting substrate for sub-canopy and understory breeding birds as well as an important food and cover resource. While dense stands of coyote willow provide valuable cover for birds, they do not provide a substantial food resource, particularly for seed and berry eating animals; additionally, because coyote willow lacks a complex structure, it is of limited value to nesting birds.

We believe that the Rio Grande Vision Plan, if enacted in its current state, will have a similar, equally devastating effect on bird numbers, as that documented in the Rio Rancho bosque. We sincerely hope that we are able to have a voice at future technical science team meetings.  It seems rather odd that the research group that has monitored bird use in the bosque for the past 10 years has not been included in the planning process.  Thank you for your attention to our concerns.

 

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