Supplement 2. Raw phenological, life history, and ecological breadth data.

Adult_Survival.csv (MD5: b05142c8e4f507949a0de4448fd1b268)

Arrival_Date.csv (MD5: cbbf8fa18b115e9f3c05fd70f5896150)

Biogeography.csv (MD5: 627fe84e1ffb74d55065f06abc2cec12)

Breeding_Date.csv (MD5: 1ab82e4d46ff6703251af676248fa1a8)

Brood_Number.csv (MD5: 6cda71ced7d80623f71bddd506904632)

Clutch_Size.csv (MD5: 5e1fd440ef3eea8046ce1e7eddc64735)

Diet_Breadth.csv (MD5: ebc8b7663bd97a86f2b64a84b12033ec)

Egg_Mass.csv (MD5: 00af1875f709dfe307fa4b688cd716b6)

Foraging_Behaviour_Breadth.csv (MD5: 34d2fec478134a29c3143b8de278af85)

Habitat_Breadth.csv (MD5: 32ed27214f2580fa521f9661807e67dc)

Nest_Site_Breadth.csv (MD5: 96ac8ff7223e5e623d2449cd1a897744)

These files contain species- and location-specific information for each of the ecological traits that we investigated.

Columns found in all files are as follows:

• Comparison: Independent comparison number, sequentially numbered, following the taxonomic order of Gill and Donsker (2010).
• Dominance: Whether species was classified as dominant or subordinate based on outcome of aggressive interactions (see Supplement 1 for details).
• Record: Unique record number for each site, year, or study from which data on a pair was gathered.
• Genus: Taxonomic genus of focal species, following Gill and Donsker (2010).
• Species: Focal species, following Gill and Donsker (2010).
• Mass: Mean mass values for each species.
• Location: Region where data were collected according to original references.
• Reference: Original reference from which ecological data were collected.

Columns unique to Arrival_Date.csv and Breeding_Date.csv

• Julian.Date: Julian date calculated from first arrival or first egg dates in original reference (mean if original reference spanned multiple years).
• Date: Original date of first arrival or first egg in original reference (mean if original reference spanned multiple years).
• Details: how first arrival or egg date was defined in original reference.

Columns unique to Clutch_Size.csv

• Clutch.Size: Clutch size from original reference (mean if original reference spanned multiple years).

Columns unique to Egg_Mass.csv

• Calculated.Fresh.Egg.Mass: Egg mass as calculated in original reference.

Columns unique to Brood_Number.csv

• Number.of.Broods.per.Year: Most common number of broods (excluding renests) produced annually for each species, from original reference.

Columns unique to Survival.csv

• Annual.Survivorship: Average probability of a breeding-age bird surviving from one year to the next from original reference (mean if original reference spanned multiple years).
• N: Number of individuals used to estimate annual survivorship.
• Notes: Method used to estimate annual survivorship and which individuals were included in original reference.

Columns unique to Diet_Breadth.csv, Foraging_Behaviour_Breadth.csv, Nest_Site_Breadth.csv, and Habitat_Breadth.csv

• X.Diversity: Calculated Shannon-Weaver index of diversity for trait of interest (mean if original reference spanned multiple years).
• X.Richness: Number of unique categories of the trait of interest observed in the original reference (mean if original reference spanned multiple years).
• N: Number of individuals included in original reference
• Notes: How the ecological trait of interest was defined in the original reference.

Columns unique to Biogeography.csv

• Breeding.Range.Size: Size of breeding range within Americas in km2 as calculated in BirdLife International and NatureServe (2011) using a Lambert Azimuthal Equal Area projection.
• Wintering.Range.Size: Size of wintering range within Americas in km2 as calculated in BirdLife International and NatureServe (2011) using a Lambert Azimuthal Equal Area projection.
• Breeding.Range.Latitude: Latitude of the centroid of breeding range within Americas in degrees as calculated from maps in BirdLife International and NatureServe (2011).
• Wintering.Range.Latitude: Latitude of the centroid of wintering range within Americas in degrees as calculated from maps in BirdLife International and NatureServe (2011).
• Breeding.Range.Longitude: Longitude of the centroid of breeding range within Americas in degrees as calculated from maps in BirdLife International and NatureServe (2011).
• Wintering.Range.Longitude: Longitude of the centroid of wintering range within Americas in degrees as calculated from maps in BirdLife International and NatureServe (2011).
• Migration.Distance: Distance in km between centroid of the breeding range and the centroid of the wintering range, estimated using an online calculator (http://www.csgnetwork.com/gpsdistcalc.html).