I recently had the opportunity to sit down with the Bosque del Apache National Wildlife Refuge Manager, Deb Williams, to ask some questions that we  heard from YOU – our Friends – after we published our original article about sandhill cranes.  You can read that original article about sandhill crane numbers here.

Read on for Deb William’s answers to questions you posed.

– Deb Caldwell, Executive Director, Friends of Bosque del Apache NWR

How are sandhill cranes doing on the refuge?

They are doing great.  According to surveys conducted in December and January, the refuge hosted upwards of 6,500 overwintering cranes during the 2022-2023 winter. Cranes could be observed on the refuge from late September through to the time of writing.  Counts from late January indicated over 4,000 cranes were still present on the refuge.

That number seems lower than in previous years.  Are cranes in decline?

The Rocky Mountain Population of sandhill cranes has been monitored since the mid 1990’s and has been reported stable with a three-year running average estimated at 23,630 birds.  But let’s provide some context.  Bosque del Apache National Wildlife Refuge lies in the southern end of the Middle Rio Grande Valley, which stretches from Cochiti Dam to Elephant Butte.  Based on historical research, an estimated eighty percent of the Rocky Mountain Population of sandhill cranes overwinters in the Middle Rio Grande Valley on average.   However, in any given year migration patterns are influenced by many factors, including weather, food resources, and water availability in proximity to food resources.  It’s important to note that this population of cranes are known to overwinter in many areas, from the Middle Rio Grande Valley to the Wilcox Playa and Sulfur Springs Valley of Arizona to the northern Mexican Highlands.  The overwintering population of cranes can be spread out in many areas in response to environmental conditions.

How many cranes did overwinter in the Middle Rio Grande Valley this past year?

Good question.  New Mexico Department of Game and Fish in collaboration with Bosque del Apache conducted the Mid-winter Waterfowl survey the week of Jan 4. A total of 13,257 cranes were observed in the Middle Rio Grande Valley. This survey effort is a snapshot in time and does not account for cranes moving into and out of the valley at various times of the year; however, it is a reliable benchmark.

How do you know what to plan for at the refuge and how do you determine management actions for the cranes?

The refuge has agreed to support the “Plan for the Management of Waterfowl and Sandhill Cranes on Federal and State Lands in the Middle Rio Grande Valley” a collaboration between state and federal agencies and stakeholders to support geese, ducks, and the Rocky Mountain Population of sandhill cranes that overwinter in the valley.  This plan outlines population trends of all the species and what percentage of each population we are trying to support at the various state and federal lands through the production of supplemental forage, such as corn or winter wheat, and native seeds, such as those grown in the refuge’s many moist soil units.  We work together to provide food across the Middle Rio Grande Valley to support our migrating feathered friends.

Here at Bosque del Apache National Wildlife Refuge, our goal is to produce enough food to support up to fifty percent of all cranes, up to fifty percent of all light geese, and up to thirty percent of all dabbling ducks that overwinter in the Middle Rio Grande Valley.  The plan tracks population trends of all species, uses models to determine caloric needs (called “use days”), and translates that information into overall poundage goals of supplemental forage and native seeds.  The poundage goals are set conservatively and assume that overwintering birds may be at a location for as many as 112 days.  We always aim to grow the same amount of food – but every migration is different in terms of total number of birds and total number of days birds overwinter in the Middle Rio Grande Valley and specifically at Bosque del Apache National Wildlife Refuge.  We aim to provide native moist-soil plant seeds to support the overwinter waterfowl and provide supplemental forage for cranes (e.g., corn and triticale).  Production is calculated for both cereal grains and native seeds that allow us to estimate ‘use-days’ for multiple guilds of bird species (cranes, ducks, and geese).

Did you meet that goal this year?

We met our overall production goals. While our corn crop did poorly this year, we had excellent production in our triticale fields and exceptional production in our native moist soil fields. Because we grow both supplemental forage and native seeds, we can meet productivity goals in a variety of combinations. The benefit of growing moist-soil plants and cereal grains is all three guilds of birds (cranes, ducks, geese) will forage on all them. Cranes will eat wetland plants, and in fact those diverse native wetland fields are like a nutritional supermarket of veggies and insects and provide higher nutritional value than a single species cereal grain field.

So, no birds were turned away due to a lack of food?

That is correct.  If there were fewer birds at the refuge this year than a certain benchmark in the past, it reflected that not as many birds proportionately overwintered in the Middle Rio Grande Valley overall.  In fact, at the time of writing there are still moist soil units full of food that we haven’t yet flooded up to make that food available to birds.

What about early in the season – is the refuge providing food and roosting habitat for early migrants?

We begin flooding select units in September to provide food and habitat for the early migrating birds.  We typically see a flush of early migrating ducks in September, primarily teal.   We often see the first early cranes in late September or early October.  These early cranes tend to stop briefly at the refuge and then continue a southward push into Mexico or over to Arizona.  The cranes that overwinter in the Middle Rio Grande Valley and on the refuge tend to arrive in November or December. This is when we see the numbers of cranes build up on the refuge.  We intentionally time the availability (flooding up and/or mowing) of food resources to coincide with the times we are seeing the largest concentrations of birds.  That is typically November through January.  But we adapt our management every year to match bird presence on the refuge.

Has this pattern of when you make food available changed over time?

No, it hasn’t.  For more than two decades we have started flooding up in September for the early flush of teal, with the bulk of the flooding occurring in November and December, tapering off in early-February.  Our aim is to have our moist soil units fed out by March 1 of each year and to match food availability to the number of birds utilizing the refuge at any given time.  What has changed over time is the total number of acres we are able to flood in any given year.  The total number of acres we manipulate and manage is directly tied to water availability, staffing, funding, and productivity of individual units.  In wet years we can put more water out on the landscape of the entire refuge as there is water available in the overall Rio Grande system.  We are currently in a twenty-year drought, with the last three years being categorized as extreme drought conditions.  Some units that were historically flooded are no longer flooded due to water efficiency and drought.  We currently have very limited resources and have focused our efforts on investing in units with high productivity, meaning they have the highest seed yields, and units we can more readily get water to.  Every fall, we survey our actively managed moist soil units for production yield by conducting seed yield surveys, which help us confirm that we are meeting the production goals.

It seemed like there were more cranes at Bernardo than at the refuge. Why is that?

There may have been. One difference I see between the two places is that Bernardo is a much smaller acreage than the refuge and their tour loop encircles all the areas the cranes are likely to be seen, making the cranes very visible in the agricultural fields.  The Bernardo unit is approximately 1675 acres.  On the refuge, cranes may be found anywhere within the approximately 10,000 acres of historic river floodplain. In 2022, approximately seventy percent of our actively managed acres were visible along the tour loop, and the remaining thirty percent of the actively managed acres were in areas closed to the public.   So, on any given day there could be a lot of cranes in areas that are closed to the public and therefore not visible.

It seems like the refuge isn’t growing as much corn as it used to, and the corn looks so much healthier at Bernardo. Why is that?

Agricultural practices at the refuge have changed a lot over the past decade.  In 2017, we went from a system where we worked with cooperative farmers to produce cereal grains to having to manage the farm program with refuge staff.  This change happened as water became more limited on the landscape. There was not enough water on the refuge to meet our endangered species management priorities as well as irrigating all of the farm fields the cooperative farmers had in production. For every twenty-five acres in production for the refuge, the cooperator had an additional seventy-five acres in production for their harvest.  We could no longer meet the irrigation needs for the cooperator’s acreages, and in 2017 transitioned into managing the farm program with our own limited staff and resources to accomplish field prepping, planting, irrigating, fertilizing and cultivating.

It has been a steep learning curve for the refuge to adopt the farming program in house. In addition to the obstacles we face with purchasing farming equipment, we also face significant challenges with soil and water quality and continued limited water. Parallel to these changes, the Middle Rio Grande Conservancy District has been investing significantly in their infrastructure to improve their efficiency at delivering water to their customers.  As we lie south of their delivery boundary, this has led to less irrigation tailwaters entering the refuge, further limiting already stressed water resources.

Corn, in particular, is a challenging crop to grow and we have been much more successful with growing triticale and other heartier cereal grains.  We also do not use any Genetically Modified Organisms (GMO) on the refuge, per USFWS policy.  Other corn producers utilize “Round-Up Ready” GMO corn seed and can broadcast spray the pesticide Round Up over the corn fields to help their corn outcompete other grasses and weeds, such as Johnson grass.

All of us in the Middle Rio Grande Valley have faced challenges with the timing of heavy monsoonal rains following drought and an inability to utilize heavy equipment in our corn fields to properly cultivate when needed.  We are currently working with partners at New Mexico State University and the University of New Mexico to examine our agricultural (cereal grain) program and help us better plan for continued water shortages so we can still meet our cereal grain production goals.  This coming season we will be focusing efforts on hearty, drought tolerant cereals grains such as wheat and sorghum varieties while we work to understand and address our soil and water quality challenges.

But if you don’t grow corn – what will the cranes eat?  And what will that do to crane numbers on the refuge?

The cranes, ducks and geese that fuel their migrations on the refuge and/or overwinter here will still have plenty of food at the refuge.  Cranes are opportunistic omnivores and may be observed eating a variety of seeds, as well as snakes, roots, or mice.

We have traditionally focused our cereal grain production on corn at the refuge because we can control its availability by mowing it, therefore ensuring that cereal grains will last all winter long.  But it’s not the only grain they will eat, cranes will forage in any cereal grain field and they were observed in large numbers all winter in our triticale fields.  But cereal grains are not necessarily the most nutritious or nutritionally balanced food. Just like for us, cereal grains provide a high carbohydrate push of calories.  Diverse native and natural foods have a better nutritional profile for all of our migrating friends and cranes forage in our moist soil units; they particularly love chufa.

Why don’t you open up more of the refuge so visitors can see the cranes?

Not all wildlife is comfortable with human presence.  Our goal is to have units at varying stages of foraging opportunity throughout the winter both along the auto tour loop and in closed areas to spread birds out and provide disturbance refugia for birds.  We intentionally plan our cereal grain fields to be both on the tour loop and in closed areas and as we manipulate (or mow) those areas to make the grains more readily available, we balance those efforts between units on and off the tour loop.  Similarly, we intentionally flood units both on and off the tour loop all winter.  In other words, we strategically manage our wetlands and farm fields to enhance visitor observation opportunities.  Our hope is to provide excellent viewing opportunities all winter long for our visitors, while still providing refuge areas for birds as well.

Our Friends members were excited to see water in the Wetland Roost area west of Highway 1, near the north boundary.  Did cranes use that area this year?

Yes, absolutely they did.  It was so incredible to see all the birds rediscover the Wetland Roost.  The heaviest use of that particular area was in the November and December timeframe.  We even filmed a fly-in at that pond for the Friend’s Virtual Crane Fiesta.  I believe the link is still active on your website if your members want to see the pond hosting cranes, geese and ducks.  Overnight roosting by large numbers of cranes and geese happened frequently, but not every night.  That area also supported a lot of mid-day loafing by snow geese.  One thing to note is that we did a lot of dirt work in that unit through late September and therefore there wasn’t any plant growth prior to flooding that could support larger numbers of ducks. Like any unit on the refuge, each day was different for how many birds utilized the unit and when they were there.

It sounds like the refuge really values both the visitor experience and the health of our crane population.  Some of our members continue to ask for specific birds counts.  It sounds like you are still conducting bird surveys, so why doesn’t the refuge post bird counts?

The refuge conducts bird surveys every other week. However, the surveys are strictly to inform our management decisions and for us to understand what resources the birds are utilizing, how spread out they are on the refuge and how much food has (or hasn’t) been consumed in our different management units.  That said, these informal surveys aren’t meant to necessarily be a full picture of every unit.  The survey effort may change from survey to survey depending on available team members or other priorities.  Further, the total count may not be tabulated for more than a week as it is not used by us for the purpose of getting a “count” of birds. Instead, this data is to help us understand where cranes, ducks, and geese are on the refuge landscape, how spread out they are and to assess and inform how and where we are making food available to the birds via the mowing and flooding of units.

When we used to provide “tallies” to visitors, the count posted in the visitor center was a bit misleading because it was already at least a week old and did not indicate where the birds were on the refuge.  Believe it or not, this caused a lot of complaints and led to a decreased visitor experience.  We found that visitors would see that number and it would give them an expectation that they would see that many birds on the tour loop.  That is not a reasonable expectation – as our tour loop, even at fourteen miles long, only covers a portion of the landscape we are managing for cranes, ducks and geese.  So, our experience was that we were setting visitors up for disappointment as they did not see what they thought they would see. Our goal is to provide opportunities to observe birds and behaviors and offer unique photographic opportunities on an amazing landscape. That is the magic of this place.  I think some visitors like to see bird counts to help them try to hit the peak numbers of winter migration, but we never know if we have hit the peak until after the peak has passed. But even being on the refuge close to that “peak” is not a guarantee that you will see more birds than a visitor who came to the refuge three weeks before that day or three weeks later as it doesn’t tell you where on the refuge landscape those birds are concentrated.

We do share the Mid-Winter Waterfowl Survey count numbers.  This survey is a nationwide effort that occurs across the US during the first week of January.  This survey is designed to be statistically significant: always occurring during the same timeframe and over the same units.  Therefore, it is comparable across years and across the United States.  It is specifically designed to determine the total number of birds. This is one of the survey efforts that helps us monitor population level trends of surveyed birds.

If we can’t convince you to post the survey numbers weekly, what can a visitor do to ensure they have the best experience while visiting the refuge?

Great question.  The first thing to do would be to plan your visit to come at the time of year and time of day to see what you are hoping to see.  We have staff and volunteers in the Visitor Center able to answer questions to help you plan your visit before you come and, on the day, – or days – you visit the refuge.  We also have volunteers that rove our tour loop during the day and report to the visitor center where they are seeing concentrations of birds to help guide our visitors to those locations.

If visitors want to see the highest number of cranes, I recommend they plan to visit during December and January.  They should plan on spending a good investment of time at the refuge – ideally an entire day.  My personal favorite experience of the cranes is fly out.  There is something magical about dawn on the refuge.  Visitors wanting to experience that could call the day before and learn where the birds roosted the previous day. It’s never a guarantee that they will roost in the same location every night, but it’s the best information we can provide.

As you know, the birds move around the refuge all day long.  Concentrated flocks of birds can shift from one hour to the next, and it’s not always predictable like fly out at dawn.  That said, there are some smart questions a visitor could ask that might help them find some insider action.  For example, what has been mowed recently? When we mow areas, whether to knock down cereal grain heads to the ground or to prepare a unit we plan to flood up, many birds (including cranes), will follow tractors to gobble up all the yummy insects, mice, snakes and other goodies that the tractors stir up.  Additionally, it’s a great time to spot our coyotes as they also key into where the tractors are working.  Another insider tip would be to ask: are any units being flooded along the auto tour loop?  It takes a long time (multiple weeks) to fully fill our larger units, but the ducks really like to feed along the edges of the water line as we fill units.  And if it’s a unit with the delectable chufa in it, you can bet there will be a lot of cranes too.


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