Social connections across migration: Do Golden-crowned sparrows (Zonotrichia atricapilla) that socialize in winter also breed together?

Here, we study migratory golden-crowned sparrows with distinct, stable winter communities. The sparrows have winter site and group fidelity across years, and birds almost always rejoin the same social community each year. Sparrows in the same tightly-knit community migrated to highly disparate locations during summer, showing that social connections in winter do not continue in summer. We provide initial evidence that the birds have entirely separate social structures across seasons with long-term social memories allowing them to reform stable groups each winter. Our research uncovers a new pattern in this model system that could apply to other migratory animals., GPS data was collected through GPS tags placed on Golden-crowned Sparrows at their wintering site at the University of California Santa Cruz (UCSC) Arboretum in California, USA. All GPS tags were programmed to take points along the birds' summer migration to the breeding grounds to see where the birds went during the breeding season. The GPS tags were archival, so data retrieval depended on physically collecting the tags when birds returned to the UCSC Arboretum field site the following winter season. We used social network analysis from visual band observations during the winter to see how these connections related to the birds' locations during the breeding season., Two data points were excluded on the breeding grounds due to a combination of unlikely travel distances and times away and only having three satellites for the fix (five or more are ideal). The points are: line #44 for bird 77968 and line #44 for bird 81324., # Social connections across migration: Do Golden-crowned Sparrows (*Zonotrichia atricapilla)* that socialize in winter also breed together?

## Description of the data and file structure

This collection of data includes the data and code used in the the paper titled above, published in the journal Wilson Field Ornithology. The Dryad files include field data of direct observations of the Golden-crowned sparrows recording their social interactions, GPS points from archival GPS tags, and scripts in the R programming language detailing all the analysis for the above paper. For full explanations of the study design, methods, and results, please see the publication.

The .csv files with ‘2016_flockingattributes.csv’ and ‘2016_flockingdata.csv’ are used in R code 2016_GCSPGPSFlockingnetwork.R.

The .txt files are used in the R code ‘GCSP_GPSdata.R.’

Details on each file

**2016_flockingattributes.csv**

A summary of the number of times each bird was seen in a flock or dominance interaction...