1. Double-crested Cormorants of the NY Harbor 2010 Harbor Herons and Waterbirds … Susan Elbin, New York City Audubon Liz Craig, New York City Audubon and Cornell University

2. Cormorants

3. Year200520062007200820092010 Nests90611751046138412181411 Islands667778 Banded0198240225255201 Double-crested Cormorant Birds Banded in the NY Harbor

7. Gulls in Jamaica Bay 2010 Update Dr. Brian E. Washburn USDA, APHIS, Wildlife Services, National Wildlife Research Center 419-625-0242 brian.e.washburn@aphis.usda.gov

9. Research Objective  Estimate the size of gull nesting populations in the Jamaica Bay Unit of Gateway NRA

10. Jamaica Bay Nest Count for 2010  20 islands & marshes  May 27 to June 8, 2010  Multi-agency effort  Count of adult gulls & count of gull nests

11. Count of Adult Gulls MarshHERGGBBG Canarsie Pol73049 Subway Island24513 Elder’s Point East602 Little Egg Marsh95120 Broad Creek Marsh 300 Duck Point Marsh60 TOTAL1,166184

12. Count of Gull Nests MarshHERGGBBG Canarsie Pol1267 Subway Island691 Elder’s Point East492 Little Egg Marsh95120 Broad Creek Marsh 300 Duck Point Marsh60 TOTAL375130

13. JFKIA HERG

14. JFKIA GBBG

15. JFKIA LAGU

16. Research Objective  Estimate the population of laughing gull nests in Jamaica Bay

17. Aerial Photography Approach

18. No estimate Number of LAGU Nests No estimate

19. Joco Marsh East High Meado w Silver Hole East Joco Island Total Colony 20071,32281331,346 20081,237132191,280 20102,6721170532,932

21. Diet of Double-crested Cormorants in NY Harbor, 2010 update Colin Grubel, CUNY Graduate Center & Queens College John Waldman, Queens College

22. Colony comparisons South Brother 4 collection trips 4 collection trips 83 items identified 83 items identified 15 sp. fish, 1 crustacean 15 sp. fish, 1 crustacean Most common sp: Hogchokers (24%) & goldfish (22%) Most common sp: Hogchokers (24%) & goldfish (22%) Swinburne 2 collection trips 72 items identified 18 sp. fish, 1 crustacean Most common sp: spotted hakes (29%)

23. Conclusions Swinburne results from trips close together Swinburne results from trips close together Can’t be easily extrapolated to rest of season Can’t be easily extrapolated to rest of season No new species found No new species found Rarity of formerly popular species (scup, black seabass) and unusual popularity of hakes may be due to Rarity of formerly popular species (scup, black seabass) and unusual popularity of hakes may be due to South Brother surveyed more thoroughly than previous years South Brother surveyed more thoroughly than previous years 1 new species (white sucker) 1 new species (white sucker) Bluegills, Lepomis macrochirus, and Pumpkinseeds, Lepomis gibbosus, usually common, not found Bluegills, Lepomis macrochirus, and Pumpkinseeds, Lepomis gibbosus, usually common, not found

24. Investigations into the Factors Affecting Pellet Production

25. Introduction Diet studies are an important part of management Boli & pellets most common methods of diet assessment Boli (regurgitated, partially digested food items) Pellets (made up of bones, scales, otoliths and other indigestible items, contained in a mucous coat and regurgitated by the birds) Otoliths are akin to ear bones of fish – highly species specific Species not represented equally between pellets and boli Good evidence of biases but no evidence as to exactly what is causing them

26. Feeding Trials Prey spininess Otolith morphology Prey size Two enclosures, housing 3 birdsTwo enclosures, housing 3 birds Floors lined with Astroturf to prevent sand accumulationFloors lined with Astroturf to prevent sand accumulation Colored glass beads inserted into fish being fed out - help quantify the time each pellet has taken to formColored glass beads inserted into fish being fed out - help quantify the time each pellet has taken to form

27. Prey Spininess Hypothesized that spines present on some species of fish may irritate the gut Would speed up pellet production Less time in gut would mean more otoliths surviving in pellet Previous fieldwork indicated spininess as a possible factor affecting pellet production 52% of fish identified in bolus samples were spiny, 48% were non–spiny 95% of fish identified in pellets were spiny, 5% were non-spiny

28. Otolith Morphologies Compact otoliths Compact otoliths Croaker Croaker Scad Scad Pinfish Pinfish goldfish goldfish Fragile otoliths Fragile otoliths Threadfin herring Threadfin herring False pilchard False pilchard Otoliths by size Croaker (avg length 10.12µ) Scad (6.94µ) Pinfish (3.7 µ ) Large threadfin (3.57 µ ) Small threadfin & false pilchard (2.53 µ ) Goldfish*

29. Conclusions The timing of pellet production may be affected my spininess of prey species but results inconclusive The timing of pellet production may be affected my spininess of prey species but results inconclusive Length of captivity appears to play a part as well, reason unknown Length of captivity appears to play a part as well, reason unknown Process may be different in wild birds Process may be different in wild birds Otolith shape can affect the likelyhood of surviving to be ejected and identified in a pellet Otolith shape can affect the likelyhood of surviving to be ejected and identified in a pellet Otolith size may also be important but more research needed Otolith size may also be important but more research needed