Saffron-cowled Blackbirds' reduced nest success in Argentina's agricultural land highlights the importance of non-agricultural habitat for its conservation

The Saffron-cowled Blackbird (Xanthopsar flavus) is a globally endangered icterid endemic to the southern South American grasslands. Temperate grasslands are among the most threatened ecosystems in South America due to their high rate of land use change. In northeastern Argentina, over the last century, the conversion of natural grasslands to livestock farming, croplands, and afforestation have resulted in significant losses of breeding habitat for the Saffron-cowled Blackbird. Consequently, it has suffered severe populational declines, and its remaining populations are fragmented. In order to understand the impact of agricultural systems on the Saffron-cowled Blackbird populations, we studied its breeding biology (clutch size, hatching success, nestling production, and fledgling success) and the main parameters that influence nest survival rate in five breeding habitat types. During the breeding seasons of 2015 to 2019 we located nests and monitored their fate. We found that the cumulative probability of nest survival over the entire nesting cycle (i.e., laying, incubation, and chick rearing) was 0.06, and was lower for nests situated in grazed land covers. Conversely, nest survival was greater in breeding sites without agricultural use, particularly in marshes. Predation was the main cause of nest failure (76%), followed by brood parasitism (10%) and trampling by cattle and agricultural machinery (6%). Brood parasitism rates were higher in grazed paddocks, contributing together with predation to the failure of nests in this habitat. Our findings indicate a negative impact of livestock ranching on Saffron-cowled Blackbird reproduction. Non-agriculture habitats, like wetlands and flooded areas, are important as refuges for nesting. Thus, the creation of breeding refuges (non-productive sites) within agricultural matrices, in association with biodiversity-friendly agricultural practices, is crucial to ensure the Saffron-cowled Blackbird's maintenance.

GENERAL INFORMATION

 

1. Dataset used for the article: Saffron-cowled Blackbirds' reduced nest success in Argentina's agricultural land highlights the importance of non-agricultural habitat for its conservation.

 

2. Study published in Ornithological Applications by Pucheta, M.F; Pereda, M.I, and Di Giacomo, A.S.

   Corresponding author email: pucheta.mf@gmail.com

   Correspondig author institution: Centro de Ecología Aplicada del Litoral, CONICET.

 

3. Date of data collection: 2015-2019

 

4. Geographic location of data collection: Argentina (Entre Ríos and Corrientes provinces). 

 

For specific data collection methods please reefer to method section of the manscript in the DOI: 10.1093/ornithapp/duae006. Journal: The Condor: Ornithological Applications

 

5. Information about funding sources that supported the collection of the data: PICT2014–3397, PICT2014–2057, PIP2022-2024, Neotropical Bird Club, Neotropical Grassland Conservancy, The Rufford Fundation, Young Conservation Leadership Program from BirdLife International and Aves Argentinas.

 

SHARING/ACCESS INFORMATION

 

1. Licenses/restrictions placed on the data: CC0 1.0 Universal (CC0 1.0) Public Domain

 

2. Links to publications that cite or use the data: Pucheta, Maria Florencia; Pereda, Maria Inés; Di Giacomo, Adrián Santiago (Forthcoming 2024). Saffron-cowled Blackbirds' reduced nest success in Argentina's  agricultural land highlights the importance of non-agricultural habitat for its conservation. Ornithological Applications.

 

3. Links to other publicly accessible locations of the data: None

 

4. Links/relationships to ancillary data sets: None

 

5. Was data derived from another source? No

A. If yes, list source(s): NA

 

6. Recommended citation for this dataset: 

Pucheta, Maria Florencia; Pereda, Maria Inés; Di Giacomo, Adrián Santiago (Forthcoming 2024). 

Data from: Saffron-cowled Blackbirds' reduced nest success in Argentina's agricultural land highlights the importance of non-agricultural habitat for its conservation.

Dryad Digital Repository. <https://doi.org/10.5061/dryad.4mw6m90hw>

 

DATA & FILE OVERVIEW

 

1. File List (nomenclature: abbreviated name of Xanthopsar flavus (xafl) + parameters presented in the datase)

 

A) xafl_Nest_Height.xlsx

B) xafl_Brood_parasitism.xlsx

C) xafl_Reproductive_Parameters.xlsx

D) xafl_Nest_Failure_Causes.xlsx

E) xafl_Nest_Survival_for_Mark.xlsx

F) xafl_Nest_Attempts.xlsx

G) xafl_Nest_survival_across_Breeding_Season.xlsx

H) xafl_Nest_Survival_and_Brood_Parasitism_Graphs

 

A) DATA-SPECIFIC INFORMATION FOR: xafl_Nest_Height.xlsx

 

1. Number of variables: 2

 

2. Number of cases/rows: 222

 

3. Variable List:

 

    * breeding_habitat: the five breeding habitat studied (marsh, roadside, hedgerow, grazed_paddock, cropland)

 

    * nest_height: height in centimeters at which each of the nests was constructed.

    

4. Missing data codes: None

 

B) DATA-SPECIFIC INFORMATION FOR: xafl_Brood_parasitism.xlsx

 

1. Number of variables: 3

 

2. Number of cases/rows: 223

 

3. Variable List:

 

    * nest_ID:the identity of each nest.

 

    * BreedingHabitat: the five breeding habitat analyzed (marsh, roadside, hedgerow, grazed_paddock, cropland)

 

    * BroodParasitism: binary variable: presence (1) or absence (0) of brood parasitism in each nest.

    

4. Missing data codes: None

 

C) DATA-SPECIFIC INFORMATION FOR: xafl_Reproductive_Parameters.xlsx

 

1. Number of variables: 9

 

2. Number of cases/rows: 107

 

3. Variable List:

 

    * Hatching_success:Hatching success per nest (number of eggs hatched over the total number of eggs laid).

 

    * Breeding_habitat_HS: reproductive habitats types for nests with information on hatching success(marsh, roadside, hedgerow, grazed_paddock, cropland).

 

    * Year_HS: the corresponding year (2015-2019) of the breeding season for which hatching success was calculated.

 

    * Clutch_size:clutch size (number of eggs) per nest.

 

    * Breeding_habitat_CS: reproductive habitats types for nests with information on clutch size.

 

    * Year_CS: the corresponding year (2015-2019) of the breeding season for which clutch size was calculated.

 

    * Fledgling_success: fledging success for each nest (chicks that successfully flew from the nest over total chicks present in the nest).

 

    * Breeding_habitat_FS: reproductive habitats types for nests with information on fledgling success.

 

    * Year_FS: the corresponding year (2015-2019) of the breeding season for which fledgling success.

 

4. Missing data codes: rows with "n/a" for nests with some parameter data not available.

 

D) DATA-SPECIFIC INFORMATION FOR: xafl_Nest_Failure_Causes.xlsx

 

1. Number of variables: 2

 

2. Number of cases/rows: 168

 

3. Variable List:

 

    * BreedingHabitat: the five breeding habitat analyzed (marsh, roadside, hedgerow, grazed_paddock, cropland).

 

    * FailureCause: the causes that led to failure in each nest (depredated, parasitated, trampling, abandonment, storms).

 

4. Missing data codes: None

 

E) DATA-SPECIFIC INFORMATION FOR: xafl_Nest_Survival_for_Mark.xlsx

 

1. Number of variables: 17

 

2. Number of cases/rows: 223

 

3. Variable List:

 

    * NestID: nest identity number

 

    * FirstFound: Julian day of the encounter date.

 

    * LastCheck: Julian day of the last date of the nest with contents.

 

    * Fate: Final status of the nest: successful (0) or failed (11).

 

    * NestAge: Days elapsed since the laying of the first egg on day 0.

 

    * year2015: Dummy variable for the year 2015 (nest of 2015 season are 1, nest from another seadon are 0).

 

    * year2016: Dummy variable for the year 2016 (nest of 2016 season are 1, nest from another seadon are 0).

 

    * year2017: Dummy variable for the year 2017 (nest of 2017 season are 1, nest from another seadon are 0).

 

    * year2018: Dummy variable for the year 2018 (nest of 2018 season are 1, nest from another seadon are 0).

 

    * Roadside:Dummy variable for the roadside habitat.

 

    * Hedgerow: Dummy variable for the hedgerow habitat.

 

    * GrazedPaddock: Dummy variable for the grazed paddock habitat.

 

    * Cropland: Dummy variable for the cropland habitat.

 

    * BroodParasitism: Binary variable for brood parasitism presence.

 

    * NestHeight: cuantitative variable measured as nest height in cm.

 

    * ColonySize: The number of total nest in the colony.

 

4. Missing data codes: None. 

 

   This dataset (E) is for Daily survival rate estimations in the software Mark, tool "Nest survival"

 

F) DATA-SPECIFIC INFORMATION FOR: xafl_Nest_Attempts.xlsx

 

1. Number of variables: 4

 

2. Number of cases/rows: 8

 

3. Variable List:

 

    * TimeOfBreeding: The progression of the breeding season expressed in fortnights.

 

    * TimeOfBreeding_name: The name assigned to each fortnight on the x-axis of the graph.

 

    * n: The number of nest attempts per fortnigh.

    

    * PercentageNestAttemps: The percentage of nest attempts per fortnight relative to the total nest attempts.

 

4. Missing data codes: None. 

 

This dataset (F) was used to plot nest attempts against the progression of the breeding season.

 

 

G) DATA-SPECIFIC INFORMATION FOR: xafl_Nest_survival_across_Breeding_Season.xlsx

 

1. Number of variables: 417

 

2. Number of cases/rows: 124

 

3. Variable List:

 

   * Breeding_time: Progression of the breeding season in days.

 

   * Daily_survival_rate: Daily survival rate calculated with MARK for each day within the breeding season.

   

   * LCI:Lower confidence interval of the daily survival rate.

 

   * UCI:Upper confidence interval of the daily survival rate.

 

4. Missing data codes: None

 

The present dataset (G) was used to plot the daily survival rate against the quadratic trend of the breeding time.

 

H) DATA-SPECIFIC INFORMATION FOR: xafl_Nest_Survival_and_Brood_Parasitism_Graphs.xlsx

 

1. Number of variables: 7

 

2. Number of cases/rows: 5

 

3. Variable List:

 

   * Environment: the five reroductive habitat analyzed (marshes, native hedgerow, croplands, roadside ditches and grazed paddocks).

 

   *Daily_survival_rate: the daily nest survival rate for the model that considers the habitat type variable.

 

   *Estandar_error: standard error for the daily survival rate (DSR) in each habitat type.

 

   * LCI: lower confidence interval for the DSR in each habitat type. 

 

   * UCI: upper confidence interval for the DSR in each habitat type. 

 

   * Brood_parasitism: the percentage of nests parasitized by habitat type.

 

   * order: the order in which the data were plotted.

 

The present dataset (H) was used to plot the daily survival rate and brood parasitism percentage against breeding habitat type.