Lakehurst Bird Surveys

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	Lakehurst Naval Base Grassland Breeding Bird Surveys 2002 - 2004

In 2004 National Biodiversity Parks, Inc. assessed the grassland breeding bird populations per US Dept. of Interior's Breeding Bird Survey and other entities' fixed point survey methods. Data was recorded for less than a 100 m radius and for greater than 100 m, using 3 minute and 5 minute time intervals at 70 points.

The chart below illustrates the populations of Upland Sandpipers, Grasshopper Sparrows, Eastern Meadowlark, Horned Lark and American Kestrel recorded on the base in 2002, 2003, and 2004. Raw data and processed data for other species, time intervals, and distances exist for 2002, 2003 and 2004 and may be available for others to examine.

Target Species	2002	2003	2004
Upland Sandpiper	24	20	30
Grasshopper Sparrow	296	288	278
Eastern Meadowlark	56	50	54
Horned Lark	4	16	18
American Kestrel	4	2	2

2003 had a wet and cool, spring and summer leading to a hypothesis that numbers of returning breeding birds might be lower in 2004 due to a higher rate of nest failure combined with fewer second clutch attempts. Low fledgling numbers in 2003 would lead to fewer first spring individuals in 2004 available to offset adult and immature mortality rates.

It was also hypothesized that the abundant rainfall had increased both plant and invertebrate biomass thereby mitigating, to some extent, the adverse weather conditions present in 2003.

Discussion of 2004 compared to 2003 results: GRSP and HOLA numbers were down 3% and 50% respectively. UPSA and EAME numbers were up 50% and 8%. AMKE remained very low at one pair.

The wet, cool conditions of 2003 may have had slight to high, negative population impacts on GRSP and HOLA. UPSA and EAME may have had high to slight, positive population trends during the same weather conditions. The two larger bodied species, with greater volume to surface ratios, are less impacted by thermoregulation stresses perhaps partially explaining the survey results.

The increase in the UPSA breeding pairs to an estimated 15 is welcomed news. Subsequent surveys will be needed to confirm any trend. Concurrent to the possible increase in UPSA at Lakehurst has been a decline or elimination of UPSA at the FAA Technical Center Airport in Pomona, NJ. UPSA are known to change breeding locations so immigration from Pomona or from other areas into Lakehurst is possible. A larger regional population picture was researched but was hampered by the Pomona contact not returning phone messages.

The drop in HOLA is not yet of concern since this specie's ethology makes it difficult to survey in a large mosaic grassland. Other species remained relatively static.

Total 2004 GRSP Population Discussion: Lakehurst is an important breeding and source population for the NJ Threatened GRSP. Based on discussions and literature search detailed in the extensive 2003 Lakehurst NBP survey report it is estimated that the base had 163 pairs (326 birds) of GRSP in 2004. Based on a literature review and the assumption that the base could be managed only for GRSP it is estimated that the maximal carrying capacity for the Base is 275 pairs of GRSP.

2004 Breeding Success: 2004 brought optimal weather for breeding birds and there is observational data to support that GRSP, AMKE and HOLA fledged in good numbers.

For example three fledged AMKE were observed, several juvenile HOLA and scores of juvenile GRSP.

Interesting was the several distinct groups of juvenile GRSP which congregated at dusk mainly on blacktop roads bordering grassland areas in West Field. Up to 19 juveniles were in a single group; they were concentrated in an area of less than 100 m 3; groups were observed in late June and early July. Then needed to be "herded off the road" (D. Temple, field notes). The relatively warm and open microhabitat of the blacktop may have been an optimal foraging area for the juveniles to locate seeds and invertebrates while socializing with other juveniles.

The spring was relatively warm with some early moderate rains followed by a dry June and early July followed by substantial rains from mid-July to the end of the summer. The hypothesis is that these three species will show increased numbers in 2005 and UPSA and EAME may also show stable to increasing numbers. This hypothesis assumes there will be no increased mortality rate for these populations during both the 2004 fall migration, winter residency and the 2005 spring migration.

Acknowledgements:Thanks to Department of Defense, M. Casper, M. Dougherty, S. Elowitz, D. Magpiong, M. Meriney, D. and J. Temple, H. Tomlinson Jr. and F. Virrazzi for their contributions.