DOI: 10.5061/dryad.2v6wwq039
title: Combining non-invasive survey methods increases cumulative detection probability for breeding Harlequin Ducks (<em>Histrionicus histrionicus</em>)

description: The effective implementation of new technologies for wildlife population
 monitoring is limited by knowledge of factors that impact their efficacy.
 Population monitoring of Harlequin Ducks (Histrionicus histrionicus) on
 their breeding streams in Montana and Idaho in the Northern Rocky
 Mountains, has historically relied on ground-based foot surveys (GBS),
 which have produced variable count data, making it hard to decipher trends
 in stream occupancy and population size. We quantified the detection
 probability of GBS and compared it to two additional non-invasive
 technologies, environmental DNA (eDNA), and camera traps (time-lapse and
 motion detection) for detecting breeding Harlequin Ducks. We surveyed for
 Harlequin Duck presence on 10 occupied streams during incubation and brood
 rearing in 2022 and 2023 using GBS, eDNA, and camera traps. We found that
 a single, five km, GBS had a mean detection probability of 0.51 (95% CI:
 0.31 – 0.71) and varied with the relative abundance of Harlequin Ducks,
 streamflow, and survey pace, but not between incubation and brood-rearing
 periods. Both eDNA and camera traps proved effective in detecting
 Harlequin Ducks, particularly when replicated across space (multiple
 samples of eDNA along a stream reach) or time (camera traps deployed over
 several weeks). It is important to note that eDNA and camera traps only
 provide presence / absence data, while GBS provides relative abundance.
 Combining methods proved particularly effective; we estimated a cumulative
 detection probability &gt;0.95 for a single-day survey effort by
 collecting eDNA samples spread throughout a stream reach in tandem with a
 GBS. Utilizing and combining these non-invasive survey techniques could
 also be used to effectively detect other low density, cryptic, waterbirds
 occupying stream habitats.
description: # Combining non-invasive survey methods increases cumulative detection
 probability for breeding Harlequin Ducks (*Histrionicus histrionicus*)
 Dataset DOI:
 [10.5061/dryad.2v6wwq039](https://doi.org/10.5061/dryad.2v6wwq039) ##
 Description of the data and file structure Final data and model code that
 was used in the paper *Combining non-invasive survey methods increases
 cumulative detection probability for breeding Harlequin Ducks
 (Histrionicus histrionicus)* by Holmes, H.A., et al. 2026. DOI:
 10.1002/wlb3.01610.  All data in this research project was collected by
 personal connected with Glacier National Park, Montana Fish, Wildlife and
 Parks, Idaho Department of Fish and Game, the USDA Forest Service,
 Northern Region, and Montana Audubon between 2022 - 2024. All data was
 gathered and cleaned, and code was written and analyzed by Holli Holmes.
 ### Files and variables **File: metadata_camera.csv**
 **Description:** Metadata with variable descriptions for
 Camera_with_all_data.csv, camera_mt.csv, and camera_tl.csv. 
 
 #### **File: Camera_with_all_data.csv** **Description:** All game camera
 data used in both the time-lapse and motion-detection game camera models.
 **Variables:** See metadata_camera.csv for full details. 
 
 #### **File: camera_mt.csv** **Description:** Game camera data used in
 the motion-detection game camera model. **Variables:**
 See metadata_camera.csv for full details. 
 
 #### **File: camera_tl.csv** **Description:** Game camera data used in
 the time-lapse game camera model. **Variables:** See metadata_camera.csv
 for full details. 
 
 #### File: metadata_eDNA.csv **Description:** Metadata with variable
 descriptions for eDNA_final_data.csv, eDNA_single_final.csv, and
 eDNA_brood_final.csv 
 
 #### File: eDNA_final_data.csv **Description:** All eDNA data used in
 both the incubation and brood rearing models. **Variables:** See
 metadata_eDNA.csv for full details. 
 
 #### File: eDNA_single_final.csv **Description:** All eDNA data used in
 the incubation detection model. **Variables:** See metadata_eDNA.csv for
 full details. 
 
 #### File: eDNA_brood_final.csv **Description:** All eDNA data used in
 the brood rearing detection model. **Variables:** See metadata_eDNA.csv
 for full details. 
 
 #### File: metadata_GBS.csv **Description:** Metadata with variable
 descriptions for GBS_final_clean_data_for_model.csv, GBS_single.csv, and
 GBS_brood.csv. 
 
 #### File: GBS_final.csv **Description:** All ground-based foot survey
 data used in both the incubation and brood rearing models. **Variables:**
 See metadata_GBS.csv for full details. 
 
 #### File: GBS_single.csv **Description:** All ground-based foot survey
 data used in the incubation detection model. **Variables:** See
 metadata_GBS.csv for full details. 
 
 #### File: GBS_brood.csv **Description:** All ground-based foot survey
 data used in the brood rearing detection model. **Variables:** See
 metadata_GBS.csv for full details. 
 
 #### File: metadata_lorlegram.csv **Description:** Metadata with variable
 descriptions for eDNA_clean_QeDNA.csv. This data was used in the lorlegram
 extra analysis. 
 
 #### File: eDNA_clean_QeDNA.csv **Description:** All eDNA data that
 includes the quantitative eDNA results. This data was used in the
 lorlegram extra analysis. **Variables:** See metadata_lorlegram.csv for
 full details. ## Code/software #### File: camera_trap_models.Rmd
 **Description:** Code for both the time-lapse and motion detection camera
 trap detection models. 
 
 #### File: Camera_trap_results.Rmd **Description:** Code showing how we
 extrapolated to the number of cameras needed to achieve detection
 probabilities of 80, 90, and 95%.  
 
 #### File: eDNA_models.Rmd **Description:** Code for both the incubation
 and brood rearing detection eDNA models. 
 
 #### File: eDNA_results.Rmd **Description:** Code showing how we
 extrapolated to the number of eDNA samples needed to achieve detection
 probabilities of 80, 90, and 95%. 
 
 #### File: GBS_analysis.Rmd **Description:** Code for both the incubation
 and brood rearing detection ground-based foot survey models. 
 
 #### File: GBS_results.Rmd **Description:** Code showing how we
 extrapolated to the number of ground-based foot surveys needed to achieve
 detection probabilities of 80, 90, and 95%. 
 
 #### File: combining_methods_cummulative_detection.Rmd
 **Description:** Code showing how we extrapolated the detection
 probability using different combinations of camera traps, eDNA, and
 ground-based foot surveys.  
 
 #### File: distance_sampling_lorelogram.R **Description:** Code for how
 we conducted the lorelogram extra analysis. ## Access information Other
 publicly accessible locations of the data: * NA Data was derived from the
 following sources: * All data was collected in the field by personal
 connected with Glacier National Park, Montana Fish, Wildlife and Parks,
 Idaho Department of Fish and Game, the USDA Forest Service, Northern
 Region, and Montana Audubon