Stewardship in Action: Trumpeter Swan nest site monitoring and habitat

improvement in Teton County, Wyoming

Drew Reed, Research Associate, Northern Rockies Conservation Cooperative

Stewardship Coordinator, Northern Rockies Trumpeter Swan Stewards

And

Ruth Shea, Research Associate, Northern Rockies Conservation Cooperative

Director, Northern Rockies Trumpeter Swan Stewards

Submitted to the

Meg and Bert Raynes Wildlife Fund

January 2016

Introduction:

This project was undertaken to monitor at least 4 Trumpeter Swan (Cygnus buccinator) nesting territories in Teton County to investigate causes of frequent nesting failures and cygnet losses. Trumpeter Swans that nest in Greater Yellowstone are the only population in the lower 48 states that was not completely destroyed by the early 1900s as the species neared extinction. This iconic population is highly valued by the community, as well as by people from around the world who know this special region. About 50-60 adult Trumpeters, usually including 10-12 nesting pairs, summer in Teton County. Their habitats face increasing human pressures and nest success in this area is often lower than in other portions of Greater Yellowstone. This swan population has been described as “conservation-reliant.” They are unlikely to thrive in the future without effective long-term management that ensures conservation of essential nesting habitats and reduces mortality factors.

In addition to monitoring we worked with Susan Patla (Wyoming Game and Fish Department) to come up with a strategy to improve the nest site at Upper Slide Lake. Moreover, it was proposed in our application to the MBRWF that we collaborate with Susan Patla on creating a private lands wetland improvement brochure. After discussion with Ruth Shea we decided the issue of how to explain to a landowner how to improve/manage a swan wetland is too subtle and complex to capture in a brochure and that we believe that a better approach is to work with WGFD to identify potential private land wetlands that might be suitable for swans with improvements, develop a relationship with the land owner and work with them one on one to understand their interests and needs for assistance and to help them in appropriate ways.

A special thank you to the Meg and Bert Raynes Wildlife Fund for funding this project!

This project was a collaborative effort of state and federal agencies and volunteers. We wish to thank the Wyoming Game and Fish Department (WGFD), United States Forest Service (USFS) Bridger Teton National Forest (BTNF), USFS Caribou-Targhee National Forest (CTNF), United States Fish and Wildlife Service National Elk Refuge (NER), and the National Park Service Grand Teton National Park (GTNP).

Methods:

Upper Slide Lake Nest Site Improvement

In late March 2016 Susan Patla WGFD, Ben Wise WGFD and I visited the site where a pair of swans typically builds a nest. Nest site failure at this territory is most likely due to nest saturation or inundation. The area was still covered in snow but we determined that best strategy to improve the site was to return after melt off but before the pair would typically initiate nesting. On 19 April, I and a volunteer returned to Upper Slide Lake. We collected grasses and willow branches from the shoreline and floated them over to the island. With the snow gone, I was able to determine that a muskrat mound was most likely the nest site. Willow branches were placed on the mound first to build it up and help create drainage to prevent saturation. Grasses were then stuffed in the willow base and on top to provide nest materials.

Nesting Territory Monitoring

Two methods were used to monitor nest success or to try and determine the causes and timing of nest failures and cygnet losses. The primary method was by mounting trail cameras at known or suspected nest site locations and territories. Cameras are a useful tool for monitoring wildlife, are more cost effective than paying a person to monitor in the field and are likely to detect more activity overall since they can remain at the site continuously. Cameras were deployed prior to the typical nest building period. All seven cameras deployed this season were setup using time interval settings. It was determined while testing the cameras prior to deployment that using the motion activated setting was not reliable enough. The primary concern was potentially using up memory card capacity and battery life due to water movement and other activity such as grass movement triggering the camera too often. The other concern was not getting enough images without knowing how close a camera could be mounted thus not triggering the camera often enough. When possible or necessary multiple cameras were deployed to capture different angles, cover more of the territory, and capture more activity. All cameras used in this project were loaned to us by WGFD.

The second method used was observations made from being on the ground or receiving information from Susan Patla WGFD after aerial surveys. These methods were used to determine if territorial pairs were present and if it was likely the pair was going to initiate a nesting attempt. These observations were conducted by GTNP staff, NER staff and volunteers, WGFD staff, and myself.

Results:

Upper Slide Lake Nest Site Improvement

Productivity Data from the past 10 years shows 3 cygnets fledged from this territory in 2004 and 2005 combined. From 2006 to 2014, a pair occupied and molted on the territory but with no nest attempt detected. However, in 2015 a pair attempted nesting here but no cygnets were ever observed. A couple of options were discussed to improve the nesting site. The first was to install an artificial floating structure. The second, was build the nest site up. Logistically the artificial island did not seem like the best option. Building the island up would take less time, cost less, and if it did not work there would be no structure to remove in the future.

With the help of a volunteer we revisited Upper Slide Lake on 19 April to build up the nest site and deploy two trail cameras. Run off had not begun and thin ice was present on the eastern half of the lake. Even with low water levels most of the island was saturated or inundated (figure1) and the suspected nest site/muskrat mound was approximately 1 foot above water level (figure 2). A significant amount of willow branches were placed on top of the mound followed by grasses to fill in

the gaps and provide nesting material and height to the nest site. Upon completion the approximate height of the nest site was 3 feet above water level, an increase of approximately 2 feet (figure 3). Before leaving two trail cameras were deployed by mounting them on stakes driven into the ground since there were no trees nearby.

Figure 1. Island pre runoff.

Figure 2. Suspected nest site prior to adding willows and grasses

Figure 3. Nest Site approximately two thirds complete

Nesting Territory Monitoring

Upper Slide Lake Territory

Two cameras were mounted to monitor activity at Upper Slide Lake. Unfortunately, both of the mounts failed. Upon returning to retrieve the cameras, one camera was found open on the ground approximately 100 feet from where it was originally mounted, was badly corroded, and chewed on. Fortunately, the SD memory card was still intact and images were downloaded for review. Although the camera mount failed, it was upright and the nest site was in view long enough to capture images from when the swans began visiting and when they appeared to have left the territory. The other camera was not found.

Trail Camera Image Summary:

Deployed: 19 April Time Interval: 30 minutes Total Number of Images: 4098

Total Usable Images: 1742 Total Images of interest: 145 Date of Last Image: 17 August

A pair of swans were present on the date of camera deployment (19 April) but were observed using the north end of the lake and out of sight from our presence. According to the images from the one camera retrieved, it appears the pair remained at the territory until 17 May. In that time, at least one swan but often two were frequently observed on the lake and at the nest site. Multiple images captured activity consistent with nest building at the site that was built up and nowhere else on the island (figure 4). There were no images that suggest that egg laying or incubation occurred. These images were also reviewed by Ruth Shea (NRCC) and Susan Patla (WGFD)

Avian predators (eagles, magpies, and ravens) were observed in numerous images on and around the nest (figure 5). Some images captured an eagle with its head down towards the nest site (figure 6). It’s likely these birds have a search image for waterfowl nest and were simply checking it for eggs.

Figure 4. Swan potentially nest building

Figure 5. An eagle and three magpies on or near nest.

Figure 6. Two eagles at nest site. One with head down near or in the nest.

Water levels were qualitatively noted while reviewing camera images. As expected during runoff, water levels fluctuated noticeably while swans were present at the territory. Some images even detected significant fluctuations within a 24 hour period. During high water events most of the island was inundated, however, the improved nest site was never observed completely inundated. There were times where the nest site was only inches above the water line. If egg laying had occurred it is likely the eggs would have become wet most likely causing a hatching to not occur. It should be noted that if she had laid eggs she would have most likely continued to build the nest up and moving eggs towards the top.

Possible territory shift?

It appears from the camera images this pair left the Upper Slide Lake territory on 17 May. This was the last date with the last definitely swan visible on this portion of the lake. Although the camera mount eventually failed, it was upright for approximately one month. During this time swans were frequently captured every day until late on 17 May. The camera eventually tilted enough to where no portion of the lake was visible on 28 May.

Susan Patla (WGFD) was conducting aerial swan nesting surveys on 7 July. During this survey, a previously undetected nest was observed in the Gros Ventre area approximately 7 miles from Upper Slide Lake. Susan reported two cygnets. It is possible given the Upper Slide Lake pair left in mid May, they shifted to a new territory. Swan incubation typically last for 30 to 35 days. This would have given them approximately 50 days to locate the new territory, build a nest, lay eggs and begin incubation in the beginning of June.

On 10 May I hiked into the new territory and set up two trail cameras to monitor the family group. Details from those observations are in the next section of this report.

Blue Miner Trail Territory

After receiving the report from Susan Patla’s aerial swan nesting survey (7 July) that a new pair with two

cygnets was detected at this new territory, I hiked in on 10 July and set up two trail cams on the east end

of the wetland. Upon arrival two adults and 5 cygnets were observed feeding near the nest (figure 7).

The cameras were quickly set up and I immediately left the area. On 3 Aug I hiked back in with Susan and Deb Patla to observe the family group. The pair and all 5 cygnets were present and appeared to be

developing well from a distance (figure 8).

After having some concerns the memory cards or batteries might expire before fledging, I hiked back in

on 29 August to set up a camera on the west end to provide a different perspective of the wetland. The

pair and 5 cygnets were still present but cygnet development appeared to be slowing (figure 9). This

wetland is visible from a nearby popular hiking trail. If people were to approach the wetland, we hoped

to get a relative idea of frequency, how much time people were spending there, and how the swan family

reacted.

Unfortunately the first two cameras mounted on the east end failed. One of the cameras mounting failed within 7 hours of deployment and shifted so that no images of interest were captured. It did record 427

images within the date of deployment. Swan family mostly feeding while in view. The other camera did

not record any images until 7 Aug at 3:36 am and recorded its last image on 7 Aug 5:46 am. All images

were in the dark and unusable. The third camera mounted on the west end remained mounted and

performed well.

Figure 7. Pair and 5 Cygnets days after hatching (10 July)

Figure 8. All 5 cygnets present and appear to be developing well (3 Aug)

Figure 9. All 5 cygnets present but may not be developing at the normal rate (23 Aug)

Trail Camera Image Summary

Failed East End Camera 1

Deployed: 10 July Time Interval: 1 minute Total Number of Images: 68,575

Total Usable Images: 427 Total Images of interest: 0 Date of Last Image: 27 August

Failed East End Camera 2

Deployed: 10 July Time Interval: 1 minute Total Number of Images: 131

Total Usable Images: 0 Total Images of interest: 0 Date of Last Image: 7 Aug

West End Camera

Deployed: 29 Aug Time Interval: 30 minute Total Number of Images: 1344

Total Usable Images: 1344 Total Images of interest: 30 Date of Last Image: 26 Sept (retrieval date)

West End Camera Summary:

This camera was deployed for approximately one month to monitor the family group towards what

should have been the fledging period. Most of the images of the family group were of them feeding on the

east end of the wetland. On 6 September at 10:00 am an image was taken showing the pair and at least

two cygnets walking up the hill near the outlet. They were approximately 100 feet from the shoreline

and heading into sparse trees. On 7 September at 4:30 pm the first image of the family feeding on the

west end near camera 3 was recorded (Figure 10). When zoomed in, it appears from this image that 2 of

the 5 cygnets are noticeably smaller. While reviewing the images, the swan family spends a significant

amount of time out of view from the camera compared to earlier from 7 September to 10 September.

From 10 September to early on 15 September the family is accounted for but very few swan images for

most of the day.

On 16 September at 6:30 am at least two adults walking up the hill near the outlet into sparse trees

(image quality won’t work for report). At 8:18 am, 16 September, Susan Patla (WGFD) observed the

family group hiking the ridge above the north end of the wetland while conducting the fall swan aerial

survey. The following morning, 17 September, Susan observed the pair and 1 cygnet from the air on a

ranch pond on West Miner Creek. 19 September Jason Wilmot (USFS) observed the pair and 1 cygnet

walking a fence line on the same ranch. Susan hiked in 20 September to the ridge above the wetland and

retrieved one dead cygnet but found no evidence of other cygnets. On 21 September, local ranch

managers located the pair and one cygnet on a pond east of Crystal Creek. The following morning, 22

September, the ranch managers returned to the pond and observed just the pair huddled together and a

bald eagle perched on the ground next to the pond (Figure 11).

It is evident from the photo Susan took of the dead cygnet at least this cygnet was developing very slowly.

The wing is essentially undeveloped and would likely mean the cygnets would not have been able to fly

before the wetland froze at the beginning of winter.

Figure 10. Swan Family observed on west end of wetland. 2 cygnets appear much smaller than other 3

Figure 11. Straight line segment distance from wetland to Crystal Creek pond approximately 2.5 miles

Arizona Lake

Arizona Lake had many nesting attempts from 2004 to 2015. Over that period 15 cygnets were reported

as hatched but no cygnets have fledged. Little swan activity had been observed at Arizona Lake prior to

the nesting season of 2016 indicating an attempt was not likely to occur. Although it was unlikely we

would document any nesting activity, one camera was set up in the area it is believed they typically nest on Arizona Lake. According to the images, no swans were utilizing this portion of the lake until mid-July.

It was not until 25 July that two swans were captured in one image and no swan activity was captured

after 27 July.

Black Rock Slough

Black Rock Slough was first documented as occupied by a pair in 2011. Since then the pair as hatched 14 cygnets but no cygnets have fledged. This territory is located in a narrow slough (approx. 50 feet at the widest point), with dense willows along most of the shoreline. One camera was set up across from the usual nest site on 1 May prior to the nesting season. The camera mount failed the first night of deployment and appears that it was caused by black bear. Although it was not in the desired position, it did capture images the entire width of the slough until 28 September. No swan images were captured at this site.

Romney Ponds (NER)

Romney Ponds was a productive site from 2007 through 2009, fledging 11 cygnets. Since 2009, a pair or individuals have been present but have not produced any cygnets. I visited Romney Ponds on 12 May after receiving a report that a pair was present. The purpose of the visit was to record potential courtship or nesting behavior and to identify the best observation points for future monitoring. A pair of swans was observed but only feeding and loafing activity was recorded. NER staff and volunteers continued to observe a pair here but there was no evidence suggesting the pair attempted to nest. No trail camera was deployed at Romney Ponds.

Elk Ranch Reservoir (GTNP)

Elk Ranch Reservoir has had a pair occupying and molting on it since 2006, however, no nesting attempts have been recorded. I visited Elk Ranch Reservoir on 19 June to determine if the pair was present. One pair of swans was observed but only swimming and feeding activity was recorded. There is no evidence suggesting the pair attempted to nest. No trail camera was deployed at Elk Ranch Reservoir.

Indian Lake (CTNF)

Reports of a swan pair at Indian Lake were made on occasion but no nesting was documented this year. No trail camera was deployed at Indian Lake.

Discussion:

Nesting Territory Monitoring

Seven swan territories were monitored throughout the nesting season of 2016 in the Jackson region. Four territories were chosen to deploy trail cameras to monitor continuously throughout the season while the other three only had ground observations since there was no apparent nesting attempt.

Nesting behavior was observed at two of the territories, however, only one territory produced cygnets. We cannot say definitely but it is possible the pair that was observed building on the nest site at Upper Slide Lake is the same pair that eventually nested and produced five cygnets at the Blue Miner Trail Wetland. According to the trail camera images the pair at Upper Slide Lake left in time to establish a nest at the Blue Miner Trail Wetland, lay eggs, and hatch them by the time they were detected during the aerial survey. If this is the case, the reason(s) for shifting territories is unknown.

Blue Miner Trail Wetland

This wetland was improved by repairing the abandoned and deteriorated beaver dam in 2009 by the Wyoming Wetlands Society. Two beaver were also released in an attempt to reestablish a colony that would maintain the dam but it did not appear beaver were active at the site in 2016. I first visited the wetland this year on 10 July to set up 2 trail cameras after Susan Patla reported cygnets hatching. From above the shallow wetland I noted the aquatic vegetation was dense and covered most of the lake bottom. Two more visits were made on 3 August and 29 August to observe the family and to set up a third camera. Aquatic vegetation appeared to still be adequate to support the family group. Susan Patla hiked in on 14 September and observed the family group feeding but noted the cygnets seemed smaller than expected. I hiked in on 26 September, 10 days after the family group abandoned the territory, to retrieve the three tail cameras. This was my first walk along the shoreline of the year and noted the vegetation was significantly less dense than previous observations from above the wetland. According to Susan’s image of the dead cygnet on the ridge, it appears the wings of this cygnet are not sufficiently developed to have enabled it to fly before the wetland would have iced over.

None of the images from the trail cameras indicate human disturbance or other disturbance around the time the family abandoned the territory. With these observations it is likely the family abandoned the territory on foot in search of more suitable foraging areas. It also appears as though all five cygnets were lost within days of abandoning the territory.

Use of Trail Cameras to monitor Swan Territories

Results from this year’s monitoring demonstrate that under the right circumstances, trail cameras can be an effective tool to provide reliable data that can be used for future swan management.

There are many factors to consider including mounting location, mounting method, camera settings, when to mount the cameras, disturbance to the pair or family, etc.

Mounting is critical to the success of utilizing trail cameras. Of the seven cameras deployed this year only two remained in the original mounting position (Blue Miner West End and Arizona Lake). Both of these were mounted on trees using bailing twine. The two cameras mounted on the east end of the Blue Miner Trail Wetland were also mounted on trees but using bungee cords so I could mount them quickly to

reduce disturbance to the family group. Two cameras mounted on stakes at Upper Slide Lake were done so since there were no trees available. At least one of these cameras remained in a position to monitor the pair while they were present at the territory but both eventually ended up on the ground. One camera was never found. The Blackrock Slough camera was mounted to a tree using bailing twine but appears a black bear moved it from its original position but the camera remained in a position to monitor the site.

Deploying multiple cameras is beneficial to capture different angles, up close images of the nest, wider angles to detect presence or absence of adults and cygnets, etc. This may not always be possible if prolonged disturbance is a concern, layout of the territory is limited, or camera availability is limited. Deploying multiple cameras with different trigger settings is also beneficial. Lithium Ion batteries and 32 gigabyte memory cards were used this year and it appears battery life and storage capacity may be a limiting factor when setup on 1 minute time intervals but not with 30 minute time intervals. Using a variety of time interval settings will increase the likelihood of documenting behaviors and activity through fledging. Using motion sensor to trigger might be beneficial at certain locations but factors such as water and vegetation movement, battery life, and memory card capacity need to be considered.

Upper Slide Lake Nest Site Improvement

In previous years, a pair has attempted to nest at Upper Slide Lake but with little or no success. The typical nest site is on a small island approximately 20 feet from the shoreline (depending on water level). Observations from previous years indicate the nest might become saturated or inundated before the cygnets hatch. Prior to the nesting season of 2016 this site was built up an additional 2 feet from original height in an attempt to prevent nest saturation or inundation. It appears from trail camera images they initiated nest building but abandoned the territory before egg laying occurred. Trail camera images show the nest site never became inundated but is difficult to know if it was ever saturated.

2016 Wyoming Fall Swan Survey

According to the USFWS 2016 fall survey, the total number of swans in Wyoming outside of YNP was 212 adults and 65 fledged cygnets. In the Jackson Region the fall survey found 61 adults and 16 cygnets in 7 broods. The Jackson region contained 29% of Wyoming’s adults and 27% of Wyoming’s fledged cygnets; most other Wyoming swans occupied wetlands in the Green River drainage.

Management Recommendations

Characteristics important for successful swan nesting include: very little to no human disturbance,

adequate forage in the form of vegetation and invertebrates, an island with sufficient nesting materials on

or in close proximity, and suitable water levels. Habitat characteristics of the seven territories monitored

this summer were not collected in a manner that can be quantified. However, observations from trail

camera images and field observations may help in understanding possible causes of failure or lack of

nesting.

Upper Slide Lake

According to trail camera images from this spring it appears that the work put it this spring to build up the nest site 2 feet was beneficial. None of the images indicate the nest site was ever inundated but water levels did get to within inches from the top of the nest. If the pair established a nest and eggs had been laid, it is likely they would have become saturated unless the pen built the nest up and moved eggs up. Several images show the island became inundated during runoff. To increase nest success in the future at this site, it is my recommendation that an area twice the size of the nest site be built up slightly for stability and the nest site itself be built up another 2 feet to help ensure it stays dry during runoff.

Blue Miner Trail Wetland

Our assumption is the pair at this new territory was the same pair observed at Upper Slide Lake in April and May. This pair was successful in hatching five cygnets. However, trail camera images, field observations, and the collection of the dead cygnet on the ridge above the wetland indicate that cygnet development was “normal” for the first month but decreased thereafter. Specifically, the collection of the dead cygnet indicates that the wings were so undeveloped that it is likely they would not have fledged before ice off. Although it was not quantified, aquatic vegetation was dense in this wetland and water levels appeared to be suitable for foraging. It is also likely that aquatic macroinvertebrates were numerous. If this family abandoned due to that lack of forage, it is likely the wetland is simply not large enough to provide adequate resources to support a family through fledging.

Blackrock Slough

No swan activity was observed at this site in 2016. A pair first occupied the territory in 2011 and was successful in hatching 14 cygnets but no cygnets have survived to fledging. Given the linear and narrow layout of this slough and dense vegetation along the edges it is likely that cygnet loss in the past is due to predation. An artificial island was installed in 2015 but was never used for nesting. If managers feel this territory is worth improving for future nesting, maintenance of the artificial island might be beneficial for nesting but may not reduce or eliminate predation of cygnets.

Arizona Lake

Arizona Lake has at least been occupied since 2004. Over a 6 year period a pair has produced 17 cygnets but no cygnets have survived to fledging. In other years the pair has attempted nesting but no cygnets hatched. Causes of nest failure and cygnet loss are unknown but given the lake’s location it’s likely avian and mammalian predators are causing cygnet loss. Nest failure could also be caused by depredation but might also be caused by high water levels. Continued monitoring with trail cameras and field observations is recommended to gain insight into the causes of these failures. Monitoring of the nest site

would be most beneficial to determine if water levels are problematic. If so, building up the nest site would likely increase hatch success.

Indian Lake, Romney Ponds and Elk Ranch Reservoir

Water levels at all three of these territories are regulated by water control structures. A better understanding of how water levels effect habitat characteristics and subsequent water management might be beneficial to swan nesting.

Budget

Project Budget Summary Table

Item Proposed Actual Comment

Salary 2,000.00 2,100.00 Field Work, Image Analysis, Report Writing

Travel 1,000.00 341.39 Mileage

Field Supplies 500.00 460.05 Cam Batteries, memory cards, field book

Materials for Habitat Improvement 1,000.00 0.00

NRCC Administration 500.00 500.00 Total: 5,000 3,401.44

Balance: 1,598.56

This was the pilot season for monitoring swans in this region using trail cameras. We had high hopes that

more pairs would have nested or at least occupied the territories so that more comprehensive

monitoring could have been conducted. We feel that using these cameras is a reliable and nonintrusive

method of collecting data at swan territories. Mounting of the cameras proved to be problematic at some

locations but we learned better techniques this year and plan to continue our efforts to monitor these

territories in the following years. Since some of the pairs did not nest this year we did not spend as much time in the field as anticipated. We would like to request from the MBRWF that we carry over the balance

of this year’s funding into 2017 to continue monitoring nest sites in the Jackson region.