Determining the Dominant Bird Species among the Northern Cardinal, Dark- eyed Junco, Tufted Titmouse, and the American Goldfinch in Lonaconing, Maryland Bird Communication • Transmit information – Food – Mates – Attacks – Escapes – Territory – Identifications • Displays – Visual Displays – Vocal Displays Agonistic Behaviors • Behaviors used when two birds interact – Hostile – Cooperative • Threat Displays (TD) – Display wings and beak – Move towards – Attacks • Submissive Displays (SD) – Turn head and beak away – Move away – Flee Dominant Bird • Use more TDs • Assert status • Move without hesitation to feeders or perch • Rank higher • Reserve access to mates, space, and food • Take fewer risks • Survive longer Subordinate Birds • Use more SDs • Move tentatively • Attacked by dominants • Have less access food • Displaced by dominant birds • Move to new locations • Have higher risk of death Dominant Interactions • Intraspecies Interactions – Older dominate younger – Males dominate females – Larger dominate smaller • Interspecies Interactions – Larger dominate smaller – More dominant depending on brain chemistry Purpose of the Study Look at the interactions between four different species of birds (Northern Cardinal, Dark-eyed Junco, Tufted Titmouse, and American Goldfinch) to determine which species is the most dominate in these interactions. Northern Cardinal • Is the largest bird – 42-48 g – 21-23 cm • Is sexually dimorphic – Males red – Females brown with red tinges • Eats seeds and fruit • Flock with other cardinals in the winter Dark-eyed Junco • Is medium-sized – 18-30 g – 14-16 cm • Vary in color – gray to brown – white underbelly • Eat mainly seeds • Flock with sparrows and bluebirds for protection Tufted Titmouse • Is a medium-sized bird – 18-26 g – 14-16 cm • Is a soft silvery gray color • Eats seeds, nuts, and berries • Flock with chickadees, nuthatches, kinglets, and woodpeckers • Is assertive to smaller birds American Goldfinch • Is the smallest bird – 11-20 g – 11-13 cm • Is sexually dimorphic only in summer • Eats mostly seeds • Flock with pine siskins and common red polls Rationale • Analyze video footage • Examine interactions among the four species • Use TDs and SDs to calculate an average Bird Threat Score (BTS) for each species • Determine which species is dominant Null Hypothesis There will be no difference in the average bird threat score among the four bird species. Alternate Hypothesis There will be a difference in the average bird threat score among the four bird species. Study Site • January 21, 2014 • Lonaconing, Maryland • Dan’s Mountain • Snowfall- 12.7cm • Temperatures- from -10 to 2.7°C Study Site • Project FeederWatch site – 2013 counts – 11 winter feeder species • Multiple feeders – Platform feeders with black-oil sunflower – Tube feeder with Nyjer seed – Tube feeders with black-oil sunflower – Suet feeders Our Feeder and Seed • Platform feeder – Easy for birds to access – Attracts large variety of bird species • Black-oil sunflower seeds – Has thin shell and easy to eat – High in fat – Favored by most bird species Study Subjects • Four bird species – Northern Cardinal (NOCA) – Dark-eye Junco (DAJU) – Tufted Titmouse (TUTI) – American Goldfinch (AMGO) Interspecies Interactions X 1. NOCA x DAJU 2. NOCA x TUTI X 3. NOCA x AMGO 4. DAJU x TUTI X 5. DAJU x AMGO X 6. TUTI x AMGO X X Video Footage • 63 minutes • Uploaded on YouTube • Divided into groups • Divided footage into 12.5 minute increments Examining Agonistic Behaviors • Threat Displays (TD) – Attacking (AT) – Moving Towards (MT) • Submissive Displays (SD) – Moving Away (MA) – Fleeing (FL) • No reaction (NR) Bird Threat Scores (BTS) • Record presence or absence agonistic behaviors • Look at both birds in an interaction • Threat Displays- – AT = 1 – MT=1 • Submissive Displays- – MA= 0 – FL=0 • No Reaction = 0 Calculating BTS • Minimum score= 0 – No presence of TD – Presence of SD and/or NR • Maximum score= 2 – Presence of both TD (AT & MT) – SD may be present • Score =1 – MT is displayed – SD may be present BTS Example Bird 1 Bird 2 MT = 1 MA= 0 AT= 1 FL= 0 BTS = 2 BTS=0 Calculating an Average BTS Sum of all the Bird Threat Scores for one species number of interactions that species was included Average BTS Example Bird 1 BTS 2 • Sample size 7 1 • Sum of BTS = 9 1 2 • Average BTS= 1.3 0 1 2 Calculating Interaction Scores • Interaction Score = BTS Bird 1 + BTS Bird 2 • Maximum score= 4 – Both birds showed both TDs • Minimum score= 0 – Both bird showed SDs or NR Interaction Score Example Bird 1 Bird 2 MT = 1 MT= 1 AT= 1 MA= 0 FL= 0 BTS = 2 BTS=1 Interaction Score = 3 Calculating the Average Interaction Scores Sum of the Interaction Scores for one type of Interspecies Interaction The number of interactions for that type of Interspecies Interaction Total Interaction of a Species • DAJU had the most Total Number of Interactions interactions for Each Bird Species 60 • NOCA had the least 50 interactions 40 30 20 10 Number of Interactions Number 0 NOCA DAJU TUTI AMGO Bird Species Average BTS for a Species Average Bird Threat Scores • TUTI had the highest for the Bird Species average BTS 0.90 • NOCA had the lowest 0.80 0.70 0.63 average BTS 0.60 • NOCA average BTS is 0.50 0.48 0.40 0.32 different from DAJU and 0.30 Average BTS Average TUTI 0.20 0.10 0.10 0.00 NOCA DAJU TUTI AMGO Bird Species Average Interaction Scores • DAJU x TUTI Average Interaction Scores for Bird average was Species Interactions 3.5 higher than 3 NOCA x DAJU 2.5 • TUTI x AMGO 2 had the highest 1.5 average 1 0.5 0 Average Interaction Score Interaction Average NOCA NOCA xNOCA x DAJU x DAJU x TUTI x x DAJU TUTI AMGO TUTI AMGO AMGO Bird Species Interactions Paired BTS • Average BTS for Each Bird in Each Interaction NOCA the only Type interactions to 1.8 have 0 scores 1.6 1.4 • All species had 1.2 1 overlapping 0.8 0.6 CI’s BTS Average 0.4 0.2 0 Species 1 Species 2 Bird Species Interactions Hypotheses Revisited • Null- There will be no difference in the average bird threat score among the four bird species. Rejected • Alternate- There will be a difference in the average bird threat score among the four bird species. Accepted Alternate Hypothesis Accepted • NOCA average is lower than DAJU and TUTI – 95% CI do not overlap • AMGO average was not different – Large 95% CI • Dominant bird not determined Problems with our Sample Size • Sample sizes were Total Bird Species Interactions low 35 • Confidence Intervals 30 29 large 25 • NOCA interactions 20 15 13 had low sample sizes 12 10 7 5 • DAJU interactions 5 4 Number of Interactions Number had larger sample 0 NOCA x NOCA x NOCA x DAJU x DAJU x TUTI x sizes DAJU TUTI AMGO TUTI AMGO AMGO Bird Species Interactions Improving Our Study • More data needed to reduce CI size – Longer videos – More days of video – More feeders with video – More sites with feeders and video – More populated sites • More research and experience identifying different bird behaviors • More practice identifying bird species Problems with Zero BTS • Zero scores Avgerage BTS for Each Bird in Each – No Reaction (NR) Interaction Type 1.8 1.6 – Submissive Displays (SD) 1.4 1.2 • Could zero scores 1 0.8 indicate dominance? 0.6 Average BTS Average 0.4 0.2 0 Species 1 Species 2 Bird Species Interactions Possible Cardinal Dominance • Do other species already know the cardinal is dominant? – Once a species is considered dominant, the number of challenges may be lower from other species (5) • Do cardinals naturally avoid other species? – Only flocks with other cardinals (1) • Do female cardinals behave differently? – No males viewed at our site Additional Questions • How do birds learn who is dominant and when do they cease to challenge dominant species? • What makes a bird species dominant? – Is brain chemistry impacting the way these four species behave? – Do age or gender play any role in interspecies interactions? – Do species behave differently depending on food source? .