DOI: 10.5061/dryad.cfxpnvxgm
title: Mistletoe-bearing trees positively influence bird foraging patterns across urban and natural environments

description: Worldwide, parasitic mistletoe species have become successful inhabitants
 of urban forests, despite novel host trees and communities of potential
 avian dispersers compared to natural habitats. Though land managers often
 remove mistletoe because of its impact on urban trees, these hemiparasites
 may nonetheless provide important food resources and structural
 heterogeneity for local avifauna. This study compares bigleaf mistletoe’s
 (Phoradendron leucarpum spp. macrophyllum) host distribution and
 relationships with birds in the urban and natural landscapes of
 California’s Central Valley. We established vegetation plots in urban
 parks and riparian forests to survey mistletoe distributions and measured
 avian visitation and behavior within individual trees. Mistletoe was
 detected in 10 of 32 surveyed tree species. Mistletoe presence did not
 vary across land-uses or tree origins (i.e., native vs. non-native trees);
 however, infestation levels were highest on larger and nonnative trees.
 Bird species richness and abundance were higher in trees with mistletoe, a
 pattern driven by insectivorous gleaning species. Birds were more likely
 to be observed foraging in trees with mistletoe in natural areas but not
 urban areas. Finally, birds observed foraging or gleaning were more likely
 to use mistletoe compared to birds observed perching. Our study reinforces
 ideas surrounding mistletoe’s host adaptability and importance for native
 birds. While prior work has focused on the importance of its berries and
 nectar, we found that mistletoe may also be important for
 invertebrate-gleaning birds. Looking forward, land managers should look to
 balance the biodiversity benefits of native mistletoe against potential
 effects on tree health.
description: # Mistletoe-bearing trees positively influence bird foraging patterns
 across urban and natural environments Dataset DOI:
 [10.5061/dryad.cfxpnvxgm](10.5061/dryad.cfxpnvxgm) ## Description of the
 data and file structure We set out to understand how mistletoe
 distributions and avian tree visitation behavior differ between urban and
 natural areas in California’s Central Valley. To do so, we surveyed tree
 communities and mistletoe across &gt;20 circular plots, 10 in natural
 areas and 11 in public parks. Across the same study system, we then
 conducted wintering bird observations at 68 focal trees, with and without
 mistletoe, noting avian visitors and their behaviors. The following files
 contains data from tree surveys, bird surveys, and traits used in both
 analyses.  ### Files and variables #### **File: BirdSurveyData.csv**
 **Description: Data recording individual trees utilized in bird
 analyses.**  ##### **Variables** * Number: The individual survey event
 unique identifier number. * Location: Abbreviated name of survey site. *
 Date Surveyed: The date of bird survey. * Time Surveyed: Time of day
 survey took place, in PST. * Latitude : Decimal degree latitude of study
 tree, ±10m.  * Longitude: Decimal degree longitude of study tree ±10m.  *
 Land Use: The land use category the tree was located in. N = natural, U =
 urban.  * Pair: The unique pair identifier shared by a tree.  * Tree sp.:
 The species of tree, indicated through a 4-letter code containing the
 first two letters of its genus and species epithet.  * Mistletoe y/n:
 Whether the tree hosted mistletoe. Y = yes, while N = No.  * Mistletoe :
 Number of mistletoe bunches in focal tree. * Fruiting: Number of mistletoe
 bunches actively fruiting. * DBH: Diameter at breast height of tree, in
 centimeters.  * Height: Height of the tree, in meters.  * Temperature:
 Temperature at time of survey start, in Farenheit.  * Wind Speed: Wind
 speed at time of survey start, in m/s.  * Weather: Weather at time of
 survey. Clear indicates less than 50% cloud cover, while overcast
 indicates cloud cover of 50% or over.  * Comments: Any comments on survey
 event.  #### **File: BirdObservationData.csv** **Description: Data
 recording bird survey visitations.**  ##### **Variables** * Tree Number:
 The unique tree identifier number the survey was conducted at,
 corresponding to same tree in BirdSurveyData.csv.  * Date Surveyed: The
 date of bird survey. * Time Surveyed: Time of day survey took place, in
 PST. * Species: Bird species observed, 4 letter ABA code * Number of
 individuals: Number of birds entering tree - only used for situations in
 which large groups (i.e. bushtits, cedar waxwings) entered tree
 simultaneously, preventing individual tracking.  * BirdID: Identifying
 number given to each bird in an individual tree.  * TimeIn: Time bird
 entered tree or mistletoe bunch. * TimeOut: Time bird left tree or
 mistletoe bunch.  * Location: Location bird entered, tree or mistletoe.  *
 Behavior: Predominant behavior displayed by bird in tree. Categories
 detailed in table S1.  #### **File: BirdTraits.csv** **Description: Trait
 data utilized in bird analyses.**  ##### **Variables** * Order: Taxonomic
 Order bird species belongs to.  * Scientific: Scientific Name. * CODE: 4
 Letter banding code. * Common: English common name. * DietGroup:
 Predominant diet group of bird species.  * ForagingStrategy:  Predominant
 foraging strategy of bird species.  * InsectGleaning: Whether the bird
 species practices insect gleaning behavior, 1 indicating yes and 0
 indicating no.  #### **File: TreeSurveyData.csv** **Description:
 Individual tree data for tree survey.**  ##### **Variables** * Plot:
 Individual plot identifier number.  * Tree_num: Tree identifier number
 within plot.  * Species_Code: 4 letter species code * DBH: Diameter at
 breast height of tree, in centimeters.  * Height: Height of the tree, in
 meters.  * distance_from_cen: Tree distance from plot center, in meters. 
 * degree: degrees from true north tree was located in relation to plot
 center * mistletoe_perc: Percentage of tree canopy volume composed of
 mistletoe bunches. * mistletoe_num: Number of individual mistletoe plants
 detected in tree.  * Dead: Whether a tree was dead or alive. #### **File:
 TreeSurveySiteAttributes.csv** **Description: Data about sites tree
 surveys took place at.**  ##### **Variables** * Site: Site name. *
 Location: Name of location site located within.  * City: City site was
 closest to, or located within.  * Land Type: The land use category the
 tree was located in. N = natural, U = urban. * Latitude: Decimal degree
 latitude of plot center, ±10m.  * Longitude: Decimal degree longitude of
 plot center ±10m.  * Date Surveyed: Date survey took place on.  ####
 **File: TreeTraits.csv** **Description: List of trees detected and
 individual trait and taxonomic information.** ##### **Variables** * Code:
 4-letter code containing the first two letters of its genus and species
 epithet, utilized in other data.  * Scientific name: Scientific name of
 tree species * Family: Taxonomic family of tree species. * Common Name:
 Common name of tree species. * Native?: Whether tree species is native or
 not. Y=yes, N=no.  * Deciduous?: Whether a tree species is deciduous or
 evergreen. D=deciduous, E=evergreen * Order: Taxonomic order of tree
 species.