Determining the Dominant Bird Species among the Northern Cardinal, Darkeyed Junco, Tufted Titmouse, and the American Goldfinch in Lonaconing,

Transcription

1 Determining the Dominant Bird Species among the Northern Cardinal, Darkeyed Junco, Tufted Titmouse, and the American Goldfinch in Lonaconing, Maryland

2 Bird Communication Transmit information Food Mates Attacks Escapes Territory Identifications Displays Visual Displays Vocal Displays

3 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

4 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

5 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

6 Dominant Interactions Intraspecies Interactions Older dominate younger Males dominate females Larger dominate smaller Interspecies Interactions Larger dominate smaller More dominant depending on brain chemistry

7 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.

8 Northern Cardinal Is the largest bird g cm Is sexually dimorphic Males red Females brown with red tinges Eats seeds and fruit Flock with other cardinals in the winter

9 Dark-eyed Junco Is medium-sized g cm Vary in color gray to brown white underbelly Eat mainly seeds Flock with sparrows and bluebirds for protection

10 Tufted Titmouse Is a medium-sized bird g cm Is a soft silvery gray color Eats seeds, nuts, and berries Flock with chickadees, nuthatches, kinglets, and woodpeckers Is assertive to smaller birds

11 American Goldfinch Is the smallest bird g cm Is sexually dimorphic only in summer Eats mostly seeds Flock with pine siskins and common red polls

12 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

13 Null Hypothesis There will be no difference in the average bird threat score among the four bird species.

14 Alternate Hypothesis There will be a difference in the average bird threat score among the four bird species.

15 Study Site January 21, 2014 Lonaconing, Maryland Dan s Mountain Snowfall- 12.7cm Temperatures- from -10 to 2.7 C

16 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

17 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

18 Study Subjects Four bird species Northern Cardinal (NOCA) Dark-eye Junco (DAJU) Tufted Titmouse (TUTI) American Goldfinch (AMGO)

19 Interspecies Interactions 1. NOCA x DAJU 2. NOCA x TUTI 3. NOCA x AMGO 4. DAJU x TUTI 5. DAJU x AMGO 6. TUTI x AMGO X X X X X X

20 Video Footage 63 minutes Uploaded on YouTube Divided into groups Divided footage into 12.5 minute increments

21 Examining Agonistic Behaviors Threat Displays (TD) Attacking (AT) Moving Towards (MT) Submissive Displays (SD) Moving Away (MA) Fleeing (FL) No reaction (NR)

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23 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

24 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

25 BTS Example Bird 1 Bird 2 MT = 1 MA= 0 AT= 1 FL= 0 BTS = 2 BTS=0

26 Calculating an Average BTS Sum of all the Bird Threat Scores for one species number of interactions that species was included

27 Average BTS Example Bird 1 BTS Sample size 7 Sum of BTS = 9 Average BTS=

28 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

29 Interaction Score Example Bird 1 Bird 2 MT = 1 MT= 1 AT= 1 MA= 0 FL= 0 BTS = 2 BTS=1 Interaction Score = 3

30 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

31 Number of Interactions Total Interaction of a Species DAJU had the most interactions NOCA had the least interactions Total Number of Interactions for Each Bird Species NOCA DAJU TUTI AMGO Bird Species

32 Average BTS Average BTS for a Species TUTI had the highest average BTS NOCA had the lowest average BTS NOCA average BTS is different from DAJU and TUTI Average Bird Threat Scores for the Bird Species NOCA DAJU TUTI AMGO Bird Species

33 Average Interaction Score Average Interaction Scores DAJU x TUTI average was higher than NOCA x DAJU TUTI x AMGO had the highest average Average Interaction Scores for Bird Species Interactions NOCA x DAJU NOCA xnoca x DAJU x TUTI AMGO TUTI DAJU x AMGO Bird Species Interactions TUTI x AMGO

34 Average BTS Paired BTS NOCA the only interactions to have 0 scores All species had overlapping CI s Average BTS for Each Bird in Each Interaction Type Species 1 Species 2 Bird Species Interactions

35 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

36 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

37 Number of Interactions Problems with our Sample Size Sample sizes were low Confidence Intervals large NOCA interactions had low sample sizes DAJU interactions had larger sample sizes Total Bird Species Interactions 12 4 NOCA x NOCA x NOCA x DAJU TUTI AMGO 5 29 DAJU x TUTI 13 DAJU x AMGO Bird Species Interactions 7 TUTI x AMGO

38 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

39 Average BTS Problems with Zero BTS Zero scores No Reaction (NR) Submissive Displays (SD) Could zero scores indicate dominance? Avgerage BTS for Each Bird in Each Interaction Type Species 1 Species 2 Bird Species Interactions

40 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

41 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?