Amendment 0001 Wild Horse and Bait Trapping IDIQ.pdf

Offers must acknowledge receipt of this amendment prior to the hour and date specified in the solicitation or as amended, by one of the following methods:

(a) By completing items 8 and 15, and returning or (c) By separate letter or electronic communication which includes a reference to the solicitation and amendment numbers. FAILURE OF YOUR ACKNOWLEDGMENT TO BE RECEIVED AT THE PLACE DESIGNATED FOR THE RECEIPT OF OFFERS PRIOR TO THE HOUR AND DATE SPECIFIED MAY RESULT IN REJECTION OF YOUR OFFER. If by virtue of this amendment you desire to change an offer already submitted, such change may be made by letter or electronic communication, provided each letter or electronic communication makes reference to the solicitation and this amendment, and is received prior to the opening hour and date specified.

E. IMPORTANT: Contractor is not is required to sign this document and return copies to the issuing office.

AMENDMENT OF SOLICITATION/MODIFICATION OF CONTRACT 1. CONTRACT ID CODE

2. AMENDMENT/MODIFICATION NUMBER 3. EFFECTIVE DATE 4. REQUISITION/PURCHASE REQUISITION NUMBER 5. PROJECT NUMBER (If applicable)

7. ADMINISTERED BY (If other than Item 6) CODE

STANDARD FORM 30 (REV. 11/2016)

Prescribed by GSA FAR (48 CFR) 53.243

FACILITY CODE

9A. AMENDMENT OF SOLICITATION NUMBER

9B. DATED (SEE ITEM 11)

10A. MODIFICATION OF CONTRACT/ORDER NUMBER

10B. DATED (SEE ITEM 13)

11. THIS ITEM ONLY APPLIES TO AMENDMENTS OF SOLICITATIONS

The above numbered solicitation is amended as set forth in Item 14. The hour and date specified for receipt of Offers is extended. is not extended.

12. ACCOUNTING AND APPROPRIATION DATA (If required) copies of the amendment; (b) By acknowledging receipt of this amendment on each copy of the offer submitted;

13. THIS ITEM APPLIES ONLY TO MODIFICATIONS OF CONTRACTS/ORDERS.

IT MODIFIES THE CONTRACT/ORDER NUMBER AS DESCRIBED IN ITEM 14.

CHECK ONE A. THIS CHANGE ORDER IS ISSUED PURSUANT TO: (Specify authority) THE CHANGES SET FORTH IN ITEM 14 ARE MADE IN THE CONTRACT ORDER

NUMBER IN ITEM 10A.

B. THE ABOVE NUMBERED CONTRACT/ORDER IS MODIFIED TO REFLECT THE ADMINISTRATIVE CHANGES (such as changes in paying office, appropriation data, etc.) SET FORTH IN ITEM 14, PURSUANT TO THE AUTHORITY OF FAR 43.103(b).

C. THIS SUPPLEMENTAL AGREEMENT IS ENTERED INTO PURSUANT TO AUTHORITY OF:

D. OTHER (Specify type of modification and authority)

Except as provided herein, all terms and conditions of the document referenced in Item 9A or 10A, as heretofore changed, remains unchanged and in full force and effect.

15C. DATE SIGNED

15A. NAME AND TITLE OF SIGNER (Type or print)

16C. DATE SIGNED

14. DESCRIPTION OF AMENDMENT/MODIFICATION (Organized by UCF section headings, including solicitation/contract subject matter where feasible.)

PAGE OF PAGES

6. ISSUED BY CODE

8. NAME AND ADDRESS OF CONTRACTOR (Number, street, county, State and ZIP Code) (X)

CODE

15B. CONTRACTOR/OFFEROR

(Signature of person authorized to sign) (Signature of Contracting Officer)

Previous edition unusable

00001 See block 16c 1060422

USDA-FS CSA SOUTHWEST 1

3644 AVTECH PARKWAY

REDDING CA 96002

127EAY22Q0055

06/04/2022

This amendment extends the response date from June 28th, 2022, 1300 Pacific to July 12th, 2022, 1300 Pacific and makes the following revisions to the solicitation that follow on the amendment continuance page:

16A. NAME AND TITLE OF CONTRACTING OFFICER (Type or print)

16B. UNITED STATES OF AMERICA

Amendment 0001 Continuance Devils Garden Wild Horse & Bait Trapping IDIQ

On page 30 of the Solicitation under Supplemental Instructions.... the page numbers are changed under Representation Provisions from (on page 37‐40) to (on page 35‐48)

Remove and Replace page 30 with the attached.

Optional Clause and Horse Census Memo and Map are made part of the Seed Task Order.

Submit pricing on the amended task order that is attached.

Electronic Submissions

(a) Quoters may submit electronic quotes as responses to this solicitation.

(b) The email address for electronic quotes is paul.wood@ usda.gov (maximum size 5MB, place solicitation number in the subject line)

(c) If any portion of a quote received by the Contracting Officer is unreadable to the degree that conformance to the essential requirements of the solicitation cannot be ascertained from the document--

(1) The Contracting Officer immediately will notify the vendor and permit resubmission of the quote.

(2) The method and time for resubmission shall be prescribed by the Contracting Officer after consultation with the vendor; and

(3) The resubmission shall be considered as if it were received at the date and time of the original unreadable submission for the purpose of determining timelines, provided the quote complies with the time and format requirements for resubmission prescribed by the Contracting Officer.

Supplemental Instructions for Submission of Offers and Other Information

(a) General Instructions. Responses to this solicitation shall be furnished in the following format with the numbers of copies as specified below:

(1) Responses shall be submitted in two parts - a technical response and a price quote. Each part shall be separate and complete in itself so that evaluation of one may be accomplished independently of the other. Price shall be submitted on the solicitation forms. The technical response is a narrative response that must not contain reference to cost; however, resource information (such as data concerning labor hours and categories, materials, subcontracts, etc.) may be contained in the technical quote so that the contractor’s understanding of the statement of work may be evaluated.

(A) Response(s) shall be submitted in the following format and the quantities specified:

(i) 1 copy of the completed, signed quote (The solicitation package)

• SF-1449, completed and signed

• Schedule of Items completed

• Representation Provisions (on page 35-48)

• Vendor shall have a current entity registration in the System for Award Management (SAM) by the closing date of the solicitation.

(ii) 1 copy of the Technical Response

(2) Quoters are cautioned that sufficient and detailed information must be presented in their technical proposals to enable the Government to evaluate their proposals fully in accordance with the evaluation and award criteria contained herein. The Government is not obligated to ask for additional information and in the absence of appropriate information the technical response will be rated deficient or unacceptable.

(3) The Government will evaluate responses in accordance with evaluation criteria as set forth herein.

(4) Responses to the Evaluation Factors for Technical Approach that form a basis for selection for award may be incorporated into the resulting contract. If this information is relied upon it may be incorporated as an appendix to the contract and become a contract promise.

(5) Price: A firm’s completion and submission of Standard Form 1449 and the Initial Task Order Schedule of Items constitutes the fulfillment of the Government’s price requirements under this solicitation.

FAR 52.212-2 Evaluation – Commercial Items (Oct 2014)

Amendment 0001

Task Order - FY22 Devils Garden Wild Horse Gather

Modoc National Forest

Section I Contract No. TBD Project Name:

2022 Wild Horse Round-Up

Requisition No. 1060422 Contractor:

Telephone:

DUNS/UEId No.

Issuing and Billing Office:

CSA#1, Redding Office 3644 Avtech Parkway Redding, CA 96002

Section II Item No.

Description Qty Method of

Measur ement

Unit

Unit Price

Amount

Base Items

001 Mobilization, Set Up & Take Down 1 CQ Lump Sum $________ $________

002 Daily Rate For A Complete Helicopter Drive-Trap Gather of up to 30 days. 30 AQ Daily $________ $________

003 Unit Price Per Head upto 500 Horses 500 AQ Per Head $ $

004 Transportation cost per loaded mile to holding facilities – Semi Trucks 0 Est. Qty Loaded Mile $________ $________

Stand-By Rate – Base Daily Operational Minus daily helicoptor rate for each daily cost.

5 AQ Daily

Total Base Items: $_________________ Optional Item***

Days extension to accomplish gather of 500 head of horses

15 AQ Daily

007a

Daily Rate Cost for a Bait Trapping Unit Price Per Head Bait Trapping

AQ

AQ

Daily

Per Head

Total All Items: $______________________

***52.217-7 OPTION FOR INCREASED QUANTITY—SEPARATELY PRICED LINE ITEM (MAR 1989)

The Government may require the delivery of the numbered line item, identified in the Schedule as an option item, in the quantity and at the price stated in the Schedule. The Contracting Officer may exercise the option by written notice to the Contractor by March 31, 2023. Delivery of added items shall continue at the same rate that like items are called for under the contract, unless the parties otherwise agree.

Section III

CONTRACTOR: (NAME AND SIGNATURE)

CONTRACTOR DUNS/UEID#:_______________________________________________________

Email:____________________________________________________________________________

***** Include your pricing with your solicitation response.

Section IV

1. DESCRIPTION OF WORK:

This project is for the capture and removal of up to approximately 500 wild horses from in and around the Devils Garden Wild Horse Territory, Devil’s Garden Ranger District, Modoc National Forest per year.

The Contractor shall furnish all labor, supplies and equipment necessary to accomplish the required work. The work consists of the capture of wild horses from the gather area, the care, feed, and transportation of the animals to a designated holding and sorting corral within 10 hours of capture at the approved trap site(s). Holding and sorting corral shall be provided by the contractor as specified herein. Contractor shall age all captured horses, feed, and provide transportation of designated animals to Forest Service holding facilities. The work shall be accomplished in a safe and humane manner in accordance with the specifications and provisions.

The Forest Service is committed to the well-being, safety, and humane and responsible care of wild horses. The contractor shall ensure humane care and treatment for wild horses during all phases of the pre-gather, gather, and post-gather process. Contractor shall, to the maximum extent practicable, prevent or minimize fear, pain, distress, suffering, risk of injury, and death while carrying out activities authorized under applicable laws, regulation, policy and specifications of this contract.

The Contractor shall, develop a plan of operations to organize, accomplish, and direct all operations for the necessary work when provided the resource objectives for the project.

2. PROJECT LOCATIONS:

Location The work consists of the capture and removal of wild horses located within the Devil’s Garden Plateau of the Modoc National Forest.

This contract is located in Modoc County, California near the town of Alturas, CA. on the Modoc National Forest.

Access

The gather areas are mostly in remote areas with rough terrain. Public, tribal, or private access roads damaged by the Contractor shall be restored, at the Contractor's expense, to the same condition they were in at the commencement of work. Vehicles shall be limited to existing designated routes. Staging areas and facilities shall be placed on designated lands.

Project Work Area

See attached map which illustrates the project area.

Trap Sites and temporary holding/sorting corral Potential trap sites and temporary holding/sorting corral locations have been identified and surveyed by the Modoc National Forest Heritage Program Manager. The sites are indicated on an attached map which illustrates the project area. Future areas might be added to map.

3. PERIOD OF PERFORMANCE

The period of performance of this project is September 1, 2022 to April 30, 2023.

Vendor shall provide a schedule as part of their technical approach.

4. SPECIFIC WORK REQUIREMENTS

This work consists of the care, feed, and transportation of the animals to a designated preparation facility within or near the Project Work Area. Captured animals shall be transported to the Forest temporary holding/sorting corral located near the territory (approximately 10 miles). The Contractor shall furnish all labor, supplies and equipment necessary to accomplish the required work, which shall include preparation of the on Forest gather /sorting corral that shall hold up to two hundred horses per day. The work shall be accomplished in a safe and humane manner and shall be in accordance with the following specifications and provisions.

The priority gathering sequence is anticipated to be as follows:

1) National Forest System lands from the Emigrant Springs and Pine Springs Allotments area east to the Laure Dam Road. To initial trap area to be exact location to be determined between COR and Contractor.

2) From Initial on site gather location to short term holding/sorting facility.

3) Transport of Captured Animals

Transport of captured animals includes stock trailer transfer from the temporary trap site(s) to the temporary holding/sorting corral and Forest Service Corrals

Specific Tasks

These gathers shall be conducted with the use of helicopter and/or horseback drive trapping, roping and bait trapping. Roping shall not be included as an extra cost for the gather. Roping shall be included in the calculation capture. Contractor shall be responsible for:

1. Trap lay out and set up with Contracting Officer's Representative (COR) notification to insure area has proper clearances.

2. Transportation of gathered animals to specified holding facility.

3. Security and feeding of animals held for 10 hours or more in the traps or holding facilities. Contractor shall provide good quality hay at the rate of not less than two pounds of hay per 100 pounds of estimated body weight per day. An animal that is held at a temporary holding facility after 5:00 p.m. and on through the night, is defined as a horse feed day. An animal that is held for only a portion of a day and is shipped or released does not constitute a feed day.

4. Support to State Brand Inspectors in handling, inspection, and/or loading of individual animals as instructed by the COR.

The Forest Service will be responsible for:

1. On-call veterinarian services.

2. Appropriate equipment for disposal of carcasses if buried in accordance with section titled Euthanasia or Death.

Task Order Pay Items Contract payment will be determined as follows

Line Item 001 – Mobilization, Operational Set Up and Take Down

A contract quantity paid as a lump sum which includes operational set up and take down, assembled drive traps, and assembled temporary holding corral for gather and sorting. Mobilization includes travel time to and from the project work area by the Contractor’s workforce; ferry time for helicopter and associated ground support. Operational set up and take down includes assembling gather/sorting corral, drive traps prior to initiation of gather, take down of drive traps, pre-gather helicopter flight time to locate horses within the project work area, and pre-work meeting with CO and/or COR as needed.

Line Item 002 - Daily Rate for a Complete Gather Approximately 500 Horses

An actual quantity daily rate during helicopter drive-trap operations. Rate includes stock trailer transport from trap sites to temporary holding/sorting corral, aging mature horses, care, feeding and watering of captured animals, security of corral and support to brand inspection(s):

1. Base daily operational cost shall include: financial compensation to cover the contractor's daily expenses plus a reasonable profit. Daily expenses shall include total contractor costs pertaining to the gather for a day including salaries, insurance, equipment, maintenance, etc., including the hourly helicopter cost minimum of 4 hours of flight time a day.

2. Complete gather daily rate shall apply regardless of the number of animals that are gathered that day. The contractor shall only be paid the actual number of days he works regardless of the number of days on the task order and the number of animals gathered.

3. Hourly rate cost if 4 hours of operations for the day is not completed.

Line Item 003 Unit Price Per Head

The contractor will be paid for the actual number of animals captured within the task order specifications. Animals captured Include:

1. Captured in the trap with all gates closed.

2. Animals herded to the trap, but not captured at the direction of the COR/PI.

3. Animals released back to the public lands at the direction of the COR/PI.

4. Animals killed or destroyed without any fault or negligence on the part of the Contractor or its employees. The contractor shall not be entitled to payment for capturing any animals which are lost, killed or destroyed during capture due to the fault or negligence on the part of the Contractor or its employees.

a. The contractor shall not be entitled to payment of recapture of animals previously released during that same gather operation and have been marked for identification purposes as being unsuitable for removal.

The contractor may be compensated for the capture of animals in excess of the 500 specified if it is determined by the Contracting Officer to be in the Government’s best interest and agreed to by both parties in a contract modification.

Line Item 004 – Transportation costs per loaded mile to all facilities.

All horse will remain at Forest Service Carrols Double Devil

Line Item 005 – Stand-By Daily Rate

A quantity daily rate for standby which includes support to base operations while on stand-by due to some unforeseen circumstance such as inclement weather or court ordered temporary restraining order which is of no fault of the contractor. Rate of base operational includes cost to feed and water any horses that have been gathered. The Stand-by rate does not include helicopter operational costs.

1) Stand-By Daily Rate if operation is required to stand-by as a result of some unforeseen circumstance.

2) If the contractor stands down for a day or a few days due to circumstances that were of no fault of the contractor), the Stand-by Daily Rate shall apply. Since the helicopter will be grounded, compensation shall be for base operational cost only.

3) It is at the discretion of the COR in consultation with the Contracting Officer and Contractor to authorize a Stand-by daily rate for the upcoming gather day.

4) If the gather is suspended due to weather after the operation has been underway, the Stand-by daily rate will apply.

5) The contractor's helicopter cost will be included to cover the contractor's complete cost for the availiblity of helicopter prior to suspension of operations that day.

6) The following will constitute a Stand-by daily rate day:

a. Weather suspension for the entire day.

b. Moving the trap(s) to another location.

7) Non-work day on Sundays or holiday shall not constitute a Stand-by work day.

8) Maintenance and/or repairs to the helicopter shall not constitute an automatic Stand-by daily rate day. The contractor shall continue working the operation. Moving traps, setting up bait stations, transporting and caring for horses etc.

Line Item 006 – Optional Extension to gather 500 head of horses.

The Government may exersice the Optional Line Item 006 through modification should the Government determine that additional time on this task, not to exceed 15 calendar days, is in the governments best intererest to meet the gather goal of upto 1000 head of horses. This line item will be actual quanitity of days speent in excess of the base 30 calendar days not to exceed 15 calendar days.

Line Item 007-Daily Rate Cost for a Bait Trapping

1) The work consists of the capture, handling, care, feeding, daily rate and transportation of wild horses to temporary holding facility. The method of capture will be with the use-of bait and/or water traps in accordance with the standards identified in the Comprehensive Animal Welfare Program (CA WP) for Wild horse and Burro Gathers.

2) The contractor shall furnish all labor, supplies, transportation, and equipment necessary to accomplish the individual task order requirements. The work shall be accomplished in a safe and humane manner and be in accordance with the· provisions of 43 CFR Part 4 700, the CA WP,

3) Forest service reserves the right to place game cameras or other cameras in the capture area to document animal activity and response, capture techniques and procedures, and humane care during trapping. No private/non-Forest Service camera will be placed within the capture areas.

4) Hazing/Driving of wild horses and burros for the purpose of trapping the animals will not be allowed for the purposes of fulfilling individual task orders. Roping will be utilized only as directed by the COR.

5) Darting of wild horses and burros for trapping purposes will not be allowed.

6) No barbed wire material shall be used in the construction of any traps or used in new construction to exclude horses or burros from water sources

7) The contractor shall assure that captured mares and their dependent foals shall not be separated for more than 4 hours unless the COR/PI determines it necessary.

8) The contractor shall provide a saddle horse on site that is available to assist with the pairing up of mares with their dependent foals and other tasks as needed.

9) Contractor will report any injuries/deaths that resulted from trapping operations as well as pre-existing conditions to the COR/PI within 12 hours of capture and will be included in daily gather activity report to the COR.

10) All trap and temporary holding facility area locations must be approved by the COR and/or the Project Inspector (PI) prior to construction and/or operation. The contractor may also be required to change or move trap locations as determined by the COR/PI. All traps and temporary holding facilities not located on public land must have prior written approval of the landowner or other management agency

11) Facility design to include traps, wings, alleys, handling pens, finger gates, shall be constructed, maintained and operated to handle the wild horses and burros in a safe and humane manner in accordance with the standards identified in the Comprehensive Animal Welfare Program (CA WP) for Wild Horse Gathers

12) Any Bait Trapping activity can be simultaneously with helicopter drive trapping, prior to drive trapping and after helicopter drive trapping.

5. FAR 52.237-1 SITE VISIT (APR 1984)

Offerors or quoters are urged and expected to inspect the site where services are to be performed and to satisfy themselves regarding all general and local conditions that may affect the cost of contract performance, to the extent that the information is reasonably obtainable. In no event shall failure to inspect the site constitute grounds for a claim after contract award.

6. GOVERNMENT FURNISHED PROPERTY:

The government may provide VHF/FM portable 2-way radios, if needed. The Contractor shall be responsible for the security of all Government Furnished Property (GFP).

7. LIST OF ATTACHMENTS

The following attachments are made a part of this solicitation and any resultant contract.

Title Pages

1. Project Map 1

2. Wage Determination 21

3. Fire Plan 6

4. Horse Census Memo and Map 12

Section V

8. EVALUATION CRITERIA:

Relevant, Price will be considered for the “Best Value” evaluation.

1. Price Evaluation for Task Order Award:

In accordance with sections L and M of the solicitation, pricing submitted on this task order will be evaluated and used for price reasonableness of both the ID/IQ awards and award of this task order.

Award Determination:

The Government anticipates awarding a single task order to the responsible vendor(s) whose quote conforming to the solicitation is most advantageous to the Government.

52.217-5 Evaluation of Options (JULY 1990) Except when it is determined in accordance with FAR 17.206(b) not to be in the Government’s best interests, the Government will evaluate offers for award purposes by adding the total price for all options to the total price for the basic requirement. Evaluation of options will not obligate the Government to exercise the option(s).

M E M O R A N D U M

To: Patrick Farris (BLM), Jenny Jayo, Madeleine Levy (USFS)

CC: Teresa Drotar (USFS), Amy Dumas, Paul Griffin, Scott Fluer, Hollè

Waddell (BLM)

From: Michelle Crabb (BLM) WHB Program Population Biologist

Date: 05/12/2022

RE: Statistical analysis for 2022 survey of horse abundance in the Devil’s Garden Plateau, CA

Summary Table

Survey Areas and Dates

Start date End date Area name Area ID

2/26/2022 2/26/2022 BLM: Red Rock Lakes HMA

USFS Allotments: Deep Lake and Mt.

Dome

CA0251

2/21/2022 2/21/2022 BLM: Round Mtn. HMA CA0252

2/23/2022 2/23/2022 USFS Allotment: East Grizzlie “

2/21/2022 2/22/2022 USFS Allotment: Emigrant Spring “

2/22/2022 2/23/2022 USFS Allotment: Pine Spring “

2/24/2022 2/24/2022 USFS Allotment: West Grizzlie “

2/22/2022 2/23/2022 USFS Allotment: Big Sage “

2/24/2022 2/24/2022 USFS Allotment: Timbered Mtn. “

2/24/2022 2/24/2022 USFS Allotments: Blue Mtn. “

2/23/2022 2/23/2022 USFS Allotments: Triangle “

2/25/2022 2/26/2022 USFS Allotment: Carr “

2/24/2022 2/25/2022 USFS Allotment: Surveyors “

2/24/2022 2/26/2022 USFS Allotment: Howards Gulch “

2/25/2022 2/25/2022 USFS Allotment: Mowitz “

2/25/2022 2/25/2022 USFS Allotment: Potters “

Survey Type Simultaneous double-observer

Aviation Details Pilot: Lucas Snyder, PJ Helicopters, Helicopter: Bell Long Ranger, #N64PS

Agency

Personnel

Observers: Patrick Farris, Madeline Levy (BLM), Chris Crosby (USFS)

Helicopter manager: Amanda Shoaf (USFS)

Summary Narrative

In February 2022 Bureau of Land Management (BLM) personnel conducted simultaneous double-observer aerial surveys of the wild horse populations in the Devil’s Garden complex and adjacent lands. The surveyed area includes the Devil’s Garden Wild Horse Territory (WHT), surrounding areas of Modoc National Forest, and Round Mountain Herd Management Area

(HMA; Figure 1A). Separately, the crew also surveyed the Red Rocks Lakes HMA and nearby

BLM and USFS lands (Figure 1B). Surveys were conducted using methods recommended by

BLM policy (BLM 2010) and the National Academy of Sciences review (NRC 2013) with detailed field methods described in Griffin et al. (2020). These data were analyzed using methods in Ekernas and Lubow (2019) to estimate sighting probabilities for horses, with sighting probabilities then used to correct the raw counts for systematic biases (undercounts) that are known to occur in aerial surveys (Lubow and Ransom 2016), and to provide confidence intervals

(which are measures of uncertainty) associated with the abundance estimates. Estimated abundance in each area is listed in Table 1, below.

Table 1. Estimated abundance (Estimate No. Horses) is for the number of horses in the surveyed areas at the time of survey. 90% confidence intervals are shown in terms of the lower limit (LCL) and upper limit (UCL). The coefficient of variation (CV) is a measure of precision; it is the standard error as a percentage of the estimated population. Number of horses seen (No. Horses Seen) leads to the estimated percentage of horses that were present in the surveyed area, but that were not recorded by any observer (Estimated % Missed). The estimated number of horses associated with each HMA (or USFS allotment) but located outside the HMA’s boundaries (Est. No. Horses Outside HMA) is already included in the total estimate for that HMA.

Area

Age

Class

Estimated

No.

Horses LCLa UCL

Std

Err CV

No.

Horses

Seen

Estimated

% Missed

Estimated

No.

Groups

Estimated

Group

Size

Foals

Per 100

Adultsb

Est. No.

Horses

Outside HMA

Private Land in and near Devils Garden

Total 117 117 137 13.3 11.4% 101 13.7% 17 6.9

0 117 Foals 0 0

Adults 117 117 137 13.3 11.4% 101

BLM Round Mtn.

HMA

Total 39 39 51 5.9 15.2% 34 12.8% 12 3.2 2.6 0

Foals 1 1 1 0 0.6% 1

Adults 38 38 50 5.9 15.6% 33

USFS Emigrant

Spring

Total 192 192 221 15 7.8% 174 9.4% 31 6.2 4.3 31

Foals 8 8 10 1.3 16.4% 7

Adults 184 184 213 14.3 7.8% 167

USFS Pine Spring

Total 175 175 208 16.5 9.4% 150 14.3% 36 4.9 7.4 29

Foals 12 12 16 1.9 15.9% 11

Adults 162 162 195 15.6 9.6% 139

USFS Big Sage Total 118 118 144 16.3 13.8% 100 15.3% 21 5.6 3.5 118

Foals 4 4 6 1.3 32.7% 3

Adults 115 115 140 15.7 13.7% 97

USFS East Grizzlie Total 20 20 29 6.5 32.7% 16 20.0% 5 4 0 18

Adults 20 20 29 6.5 32.7% 16

USFS West Grizzlie Total 9 9 16 4.5 49.9% 6 33.3% 3 3 0 9

Adults 9 9 16 4.5 49.9% 6

USFS Timbered Mtn. Total 103 103 124 11.4 11.0% 86 16.5% 23 4.5 0 8

Adults 103 103 124 11.4 11.0%

Table 1, Cont.Area Age

Class

Est No.

Horses

LCLa UCL Std

Err

CV Horses

Seen

Est. %

Missed

Est. No

Groups

Est. Group

Size

Foals / 100

Adults

Est. No. Horses

Outside HMA

USFS Triangle Total 67 67 83 9.8 14.6% 59 11.9% 13 5.2 1.5 13 Foals 1 1 1 0.1 14.7% 1 Adults 66 66 82 9.7 14.8% 58

USFS Blue Mtn. Total 27 27 36 6 22.4% 24 11.1% 5 5.4 0 27

Adults 27 27 36 6 22.4% 24

USFS Carr Total 204 204 225 12.9 6.3% 188 7.8% 38 5.4 5.7 23

Foals 11 11 14 1.7 15.3% 10

Adults 193 193 214 12.2 6.3% 178

USFS Surveyors Total 57 57 66 6.7 11.7% 49 14.0% 15 3.8 1.8 0

Foals 1 1 2 0.5 52.4% 1

Adults 56 56 65 6.5 11.6% 48

USFS Howards

Gulch

Total 60 60 74 7.4 12.3% 51 15.0% 12 5 0 60

Adults 60 60 74 7.4 12.3% 51

USFS Mowitz Total 17 17 23 3.9 23.2% 14 17.6% 6 2.8 0 10

Adults 17 17 23 3.9 23.2% 14

USFS Potters Total 0 0 0

USFS Sub Total Total 1,049 1,049 1,133 45.7 4.4% 917 12.6% 208 5 3.7 346

Foals 37 37 43 3.6 9.7% 33 Adults 1,012 1,012 1,089 44.2 4.4% 884

Devil’s Garden

Complex Total

Total 1,205 1,205 1,299 51.7 4.3% 1,052 12.7% 237 5.1 3.3 463 Foals 38 38 44 3.6 9.4% 34 Adults 1,167 1,167 1,257 50.2 4.3% 1,018

BLM Red Rock

Lakes HMA and vicinity

Total 61 61 68 4.3 7.0% 59 3.3% 4 15.2 3.4 61 Foals 2 2 2 0 0.1% 2 Adults 59 59 66 4.3 7.2% 57

Survey Total Total 1,266 1,266 1,361 52.5 4.1% 1,111 12.2% 241 5.3 3.3 524 Foals 40 40 46 3.6 9.0% 36 Adults 1,226 1,226 1,317 51 4.2% 1,075 a The lower 90% confidence limit is based on bootstrap simulation results or the number of horses seen, whichever is higher.

b The estimated ratio of foals to adults reflects what was observed during this February survey and does not represent the full cohort of foals for this year.

Abundance Results

The estimated total horse abundance within the surveyed area is reported in Table 1. Observers recorded 197 horse groups, of which 186 horse groups had data recorded properly 'on protocol' and that could be used to compute statistical estimates of sighting probability. Of the 197 groups seen, all 197 observations were used to calculate the abundance estimate. Any horse groups that were seen on two separate occasions (i.e., double counted), or that were identified as domestic and privately owned, were not used to calculate abundance; however, such groups can be used to parameterize sighting probability if they were recorded on protocol. Coefficient of variation

(Table 1) values of less than 10% indicate high precision resulting from high detection probabilities; values between 10-20% indicate medium precision resulting from lower detection probabilities; and values greater than 20% indicate low precision resulting from very low detection probabilities.

The mean estimated size of detected horse groups, after correcting for missed groups was 5.3 horses/group across the surveyed area, with a median of 4 horses/group. There were an estimated

3.3 foals per 100 adult horses at the time of these surveys (Table 1). Surveys flown before July are unlikely to include all foals born this year, while surveys flown during or after July would not include foals that were born this year but died before the survey.

Sighting Probability Results

The combined front observers saw 67.2% of the horse groups (76.6% of the horses) seen by any observer, whereas the back seat observers saw 73.7% of all horse groups (79.0% of horses) seen

(Table 2). At least one observer (front or back) missed 59.1% of horse groups seen by the other.

These results demonstrate that simple raw counts do not fully reflect the true abundance without statistical corrections for missed groups, made possible by the double observer method and reported here. Direct counts from aerial surveys underestimate true abundance because some animals are missed by all observers; this analysis corrects for that bias (Lubow and Ransom

2016). The analysis method used for the surveyed areas was based on simultaneous double-observer data collected during these surveys.

The sample size of observations following protocol was 186 horse groups. Survey datasets with sample sizes of 41-100 groups are moderate and can estimate effects of many but likely not all potential sightability covariates; and sample sizes >100 groups are large and can account for most sightability covariates.

All models used in the double-observer analysis contained an estimated intercept common to all observers. Informed by a priori reasoning and preliminary analyses showing overwhelming support, I also included an additional parameter in all models for effect of: (1) horse group size;

(2) observations by front-seat observers; and (3) back-seat observers. I evaluated 6 possible effects on sighting probability by fitting models for all possible combinations with and without the following additional effects, resulting in 64 alternative models. The 6 effects examined were:

(1) horse group activity; (2) high lighting conditions; (3) percent vegetation cover; (4) percent snow cover; (5) tree visual field (with broken included); and (6) observer PF in the back-seat.

Due to weak support during preliminary analyses and opposite directionality from expected, I did not consider effects on detection probability of distance of horses from the flight path. I did not consider effects on detection probability of rugged topography due to insufficient variation in the values of this covariate. Covariates and their relative effect on sighting probability are shown in

Table 3.

There was moderate support for an effect of high lighting conditions (60.9% of AICc model weight), moving animals (41.2%), PF in the backseat (61.6%), percent vegetation cover (38.9%), and tree visual field (35.7%), and weak support for the effect of snow cover (30.5%). As expected, visibility was higher for horse groups that were larger, moving, and lower for groups on the pilot side, in snow cover, in vegetation cover, and in tree cover (Table 3). Contrary to what is expected visibility was lower for groups in high lighting conditions.

Groups that were recorded on the centerline, directly under the aircraft, were not available to backseat observers. For these groups, backseat observers' sighting probability was therefore set to 0. Sighting probability for groups visible on both sides of the aircraft was computed based on the assumption that both backseat observers could have independently seen them, thereby increasing total detection probability for these groups relative to groups available to only one side of the helicopter.

Estimated overall sighting probabilities, �̂�, for the combined observers ranged across horse groups from 0.51-1.00. Sighting probability was <0.7 for 31 (16%), and <0.6 for 4 (2%) of observed groups. In aggregate across all observed groups, the overall “correction factor” that was added on to the total number of wild horses seen was 14.2%. That is to say: 1,111 horses were seen, and adding another 14.2% of that number seen equals the total estimate of 1,266 horses

(Table 1). A different but mathematically equivalent interpretation is listed in Table 1 in the

“Estimated % Missed” column, which shows that, overall, 12.2% of the horses that were estimated to be present during the survey were never seen by any of the observers (Table 1).

Assumptions and Caveats

Results from this double observer analysis are a conservative estimate of abundance. True abundance values are likely to be higher, not lower, than abundance estimates in Table 1 because of several potential sources of bias listed below. Results should always be interpreted with a clear understanding of the assumptions and implications.

1. The results obtained from these surveys are estimates of the horses present in the surveyed area at the time of the survey and should not be used to make inferences beyond this context.

Abundance values reported here may vary from the annual March 1 population estimates for the

HMA; aerial survey data are just one component of all the available information that BLM uses to make March 1 population estimates. Aerial surveys only provide information about the area surveyed at the time of the survey, and do not account for births, deaths, movements, or any management removals that may have taken place afterwards.

2. Simultaneous double-observer analyses cannot account for undocumented animal movement between, within, or outside of the surveyed area. Fences and topographic barriers can provide deterrents to animal movement, but even these barriers may not present continuous, unbroken, or impenetrable barriers. It is possible that the surveys did not extend as far beyond a boundary as horses might move. Consequently, there is the possibility that temporary emigration from the surveyed area may have contributed to some animals that are normally resident having not being present at the time of survey. In principle, if the level of such movement were high, then the number of animals found within the survey area at another time could differ substantially. If there were any wild horses that are part of a local herd but were outside the surveyed areas, then

Table 1 underestimates true abundance.

3. The validity of the analysis rests on the assumption that all groups of animals are flown over once during a survey period, and thus have exactly one chance to be counted by the front and back seat observers, or that groups flown over more than once are identified and considered only once in the analysis. Animal movements during a survey can potentially bias results if those movements result in unintentional over- or under-counting of horses. Groups counted more than once would constitute ‘double counting,’ which would lead to estimates that are biased higher than the true number of groups present. Groups that were never available to be seen (for example due to temporary emigration out of the study area or undetected movement from an unsurveyed area to an already-surveyed area) can lead to estimates that are negatively biased compared to the true abundance.

Survey SOPs (Griffin et al. 2020) call for observers to identify and record ‘marker’ animals (with unusual coloration) on paper, and variation in group sizes helps reduce the risk of double counting during aerial surveys. Observers are also to take photographs of many observed groups and use those photos after landing to identify any groups that might have been inadvertently recorded twice. Unfortunately, there is no effective way to correct for the converse problem of horses fleeing and thus never having the opportunity for being detected. Because observers can account for horse movements leading to double counting, but cannot account for movement causing horses to never be observed, animal movements can contribute to the estimated abundance (Table 1) potentially being lower than true abundance.

4. The simultaneous double-observer method assumes that all horse groups with identical sighting covariate values have equal sighting probability. If there is additional variability in sighting probability not accounted for in the sighting models, such heterogeneity could lead to a negative bias (underestimate) of abundance. In other words, under most conditions the double-observer method underestimates abundance.

5. The analysis assumes that the number of animals in each group is counted accurately.

Standard Operating Procedures (Griffin et al. 2020) specify that all groups with more than 20 animals are photographed and photos scrutinized after the flight to correct counts. Smaller groups, particularly ones with poor sighting conditions such as heavy tree cover, could also be undercounted. Any such undercounting would lead to biased estimates of abundance.

Evaluation of Survey and Recommendations

It appears that survey protocols were followed well. The number of crew members was limited to the minimum possible (3 observers and 1 pilot), which is highly desirable for obtaining precise estimates. Observers were sufficiently experienced and trained, and visibility conditions were generally good, except for the first day when it was fair.

The survey covered all parts of the WHT and HMAs. The survey did not extend to the northern boundaries of the Blue Mtn., West Grizzlie, and East Grizzlie allotments. This leaves open the possibility that more horses were present in the unsurveyed portions of these USFS allotments.

The survey extended beyond the boundaries of the WHT, HMAs, and USFS allotments into some areas of private land where horses were observed, sometimes near the edge of the surveyed area. However, additional private land appears to be accessible to horses beyond the areas surveyed, so the estimates for private land derived from these data cannot be interpreted as a complete assessment of the extent of wild horse occupancy and use of these lands. There are no obvious natural deterrents to horse movements that would contain them within the boundaries of the survey area. Consequently, it is difficult to be sure there were no additional horses outside of the WHT, HMAs, and USFS allotments in areas not surveyed, and results should be understood to represent the horses present only in the area surveyed, which may not represent all horses that occasionally occupy the Devil’s Garden complex and immediate vicinity. Careful consideration should be given to where horses were located near the edge of the area surveyed when planning whether to extend the survey area further in future surveys to ensure covering all areas potentially occupied by horses associated with the HMAs, or to confirm that the current survey boundaries do cover the full extent of horses’ range in this area.

Table 2. Tally of raw counts of horses and horse groups by observer (front, back, and both) for

Devil’s Garden Plateau, and vicinity of Red Rock Lakes HMA, surveyed in February 2022.

Observer

Groups seena

(raw count)

Horses seen

(raw count)

Actual sighting rateb (groups)

Actual sighting rateb (horses)

Front 125 778 67.2% 76.6%

Back 137 803 73.7% 79.0%

Both 76 565 40.9% 55.6%

Combined 186 1016 a Includes only groups and horses where protocol was followed.

b Percentage of all groups seen that were seen by each observer.

Table 3. Effect of observers and sighting condition covariates on estimated sighting probability of horse groups for both front and rear observers during the February 2022 survey of the Devil’s

Garden Plateau. Baseline case (bold) for horses presents the predicted sighting probability for a group of 4 horses (the median group size observed), in 0% vegetation cover, not moving, not in tree visual field, not in high light, not on the pilot side, and with the average back-seat observer.

Other example cases vary a covariate or observer, one effect at time, as indicated in the left-most column, to illustrate the relative magnitude of each effect. Sighting probabilities for each row should be compared to the baseline (first row) to see the effect of the change in each observer or condition. Baseline values are shown in bold wherever they occur. Sighting probabilities are weighted averages across all 64 models considered (Burnham and Anderson 2002).

Sighting probability

Front

Observera

Back

Observerb

Combined

Observers

Baseline 75.8% 67.2% 92.1%

Effect of group size (N=1) 69.3% 59.6% 87.6%

Effect of group size (N=10) 85.8% 79.7% 97.1%

Effect of Veg= 30% 73.2% 64% 90.4%

Effect of Veg= 60% 70.0% 60.5% 88.2%

Effect of Moving 78.7% 70.7% 93.8%

Effect of Trees 73.5% 64.4% 90.6%

Effect of Snow=30% 75.3% 66.6% 91.8%

Effect of Snow= 60% 74.8% 66.0% 91.4%

Effect of High light 68.4% 58.5% 86.9%

Effect of Pilot’s Side 38.4% 67.2% 79.8%

Effect of Observer PF 75.8% 75.4% 94.0%

Effect of back=front 75.8% 75.8% 94.1% a Sighting probability for the front observers acting as a team, regardless of which of the front observers saw the horses first.

b Sighting probabilities for back observers for horse groups that are potentially visible on the same side of the aircraft as the observer. Sighting probability in the back is 0 for groups on the opposite side or centerline.

Literature Cited

Bureau of Land Management. 2010. Wild horse and burro population inventory and estimation:

Bureau of Land Management Instructional Memorandum No. 2010-057. 4 p.

Burnham, K., and D. R. Anderson. 2002. Model Selection and Multimodel Inference: A Practical

Information-Theoretic Approach. Springer-Verlag, New York, New York.

Ekernas, L. S., and B. C. Lubow. 2019. R script to analyze wild horse and burro double-observer aerial surveys. USGS Software Release.

Griffin, P. C., L.S. Ekernas, K.A. Schoenecker, and B. C. Lubow. 2020. Standard Operating

Procedures for wild horse and burro double-observer aerial surveys. U.S. Geological Survey

Techniques and Methods, book 2, chap. A16, 76 p., https://doi.org/10.3133/tm2A16.

Lubow, B. C., and J. I. Ransom. 2016. Practical bias correction in aerial surveys of large mammals: validation of hybrid double-observer with sightability method against known abundance of feral horse (Equus caballus) populations. PLoS-ONE 11(5):e0154902.

doi:10.1371/journal.pone.0154902.

National Research Council. 2013. Using Science to Improve the BLM Wild Horse and Burro

Program. The National Academies Press. Washington, D.C.

Figure 1. Map of 2022 Devil’s Garden WHT and Round Mountain HMA region (A) and Red Rock Lakes HMA region (B) survey tracks flown (black lines), approximate locations of observed horse groups (black and white circles), HMA boundaries (blue), and USFS Allotment boundaries (purple).

A.) Devil’s Garden WHT and Round Mountain HMA and vicinity

B.) Red Rock Lakes HMA and vicinity