January flights for the Delaware aerial waterfowl counts published by the Division of Fish and Wildlife began in 1975. Using five-year groups, brant averages for each January zone row reached 202 during 1975 to 1979 and 200 during 2000 to 2004. From 2010 onward, each finished block's mean has fallen in the 44 to 50 range. The two January flights completed so far for the 2025 block have a mean of 69.
IJanuary patterns
Brant stayed near 200 through the early 2000s before falling after 2010
The decline did not follow a gradual downward path. Brant averages fell to 79 for each zone row during 1990 to 1994 before recovering first to 186 and later to 200. The average then dropped to 119 during 2005 to 2009 before reaching 46 during 2010 to 2014. Each zone row represents a single survey zone during a single flight. These figures count birds observers saw from the aircraft rather than estimating the population.
Canada geese in October followed another pattern. Their averages for each zone row were 12,440 during 1975 to 1979 and 12,369 during 1980 to 1984. By 1990 to 1994 the average had dropped to 3,400. From 2010 onward, block averages have ranged from 1,443 to 2,641. Across five-year periods, December snow goose averages have varied sharply from 26,397 during 2010 to 2014 down to 3,378 during 2020 to 2024.
Swipe table to see every column
| Years | January surveys | Brant, January | Brant, December | Canada goose, October | Snow goose, December |
|---|---|---|---|---|---|
| 1970 to 1974 | 0 | n/a | 36 | 7,977 | 289 |
| 1975 to 1979 | 5 | 202 | 260 | 12,440 | 446 |
| 1980 to 1984 | 5 | 185 | 161 | 12,369 | 1,542 |
| 1985 to 1989 | 5 | 115 | 43 | 8,847 | 2,284 |
| 1990 to 1994 | 5 | 79 | 75 | 3,400 | 12,452 |
| 1995 to 1999 | 5 | 186 | 101 | 2,287 | 11,646 |
| 2000 to 2004 | 5 | 200 | 210 | 3,373 | 16,415 |
| 2005 to 2009 | 5 | 119 | 102 | 2,618 | 15,068 |
| 2010 to 2014 | 5 | 46 | 12 | 1,930 | 26,397 |
| 2015 to 2019 | 5 | 44 | 53 | 1,443 | 12,728 |
| 2020 to 2024 | 5 | 50 | 62 | 1,778 | 3,378 |
| 2025 to 2029 | 2 | 69 | 0 | 2,641 | 27,903 |
IISeasonal counts
Brant rise starting in November and reach their high in January during both eras
Comparing the eras brings the seasonal pattern into view. The averages for 1974 to 1989 were 9 brant per zone row for October, 140 for November, 148 for December and 167 for January. During 2010 to 2026 those monthly averages were 5, 29, 39 and 49. January led each era.
The monthly ranking shifted for Canada geese. October led the earlier era with an average of 11,009 for each zone row. In the later era, October ranks last at 1,713 and the average rises month by month to January's 3,284. Snow geese now reach their high in December with 15,470 for each zone row, a month later than November's 2,315 in the earlier era. Our duck side of this survey examines ducks along with further detail on the seasonal timing of Canada geese and snow geese.
Swipe table to see every column
| Species | Era | October | November | December | January |
|---|---|---|---|---|---|
| Atlantic brant | Early (1974 to 1989) | 9 | 140 | 148 | 167 |
| Atlantic brant | Late (2010 to 2026) | 5 | 29 | 39 | 49 |
| Canada goose | Early (1974 to 1989) | 11,009 | 4,599 | 4,759 | 4,979 |
| Canada goose | Late (2010 to 2026) | 1,713 | 2,135 | 2,886 | 3,284 |
| Snow goose | Early (1974 to 1989) | 1,997 | 2,315 | 1,353 | 587 |
| Snow goose | Late (2010 to 2026) | 981 | 3,271 | 15,470 | 9,333 |
IIIReading harvest
Delaware estimates are too uncertain for judging individual seasons and flyway harvest varies sharply
The federal reports on migratory bird hunting activity and harvest provide state estimates for harvested brant. Delaware's seasonal estimates ranged from 300 to 1,700 for 1999-2000 through 2009-2010. From 2010-2011 onward the range was 100 to 600. These survey estimates use rounding to the closest 100, and their published CVs span 38 to 141 percent. CV means coefficient of variation and expresses standard error relative to the estimate. At 100 percent the standard error matches the estimate's size, so we draw only a loose reading from those two ranges.
For a broader comparison, Atlantic Flyway brant harvest stood at 18,400 for 1999-2000 and 8,700 for 2024-2025. Between those seasons the high was 44,700 and the low was 3,700. The peak occurred during 2003-2004 and the bottom during 2022-2023. For every season with a Delaware estimate, the New Jersey estimate exceeds it. No Delaware brant estimate appears in the reports for either 2014-2015 or 2022-2023.
Swipe table to see every column
| Season | Delaware | Delaware CV percent | New Jersey | Atlantic Flyway |
|---|---|---|---|---|
| 1999-2000 | 1,500 | 84 | 6,700 | 18,400 |
| 2000-2001 | 1,700 | 104 | 5,800 | 25,000 |
| 2001-2002 | 300 | 63 | 6,800 | 24,500 |
| 2002-2003 | 1,600 | 38 | 9,800 | 33,400 |
| 2003-2004 | 1,500 | 52 | 9,900 | 44,700 |
| 2004-2005 | 600 | 60 | 5,000 | 15,800 |
| 2005-2006 | 1,500 | 53 | 8,300 | 30,400 |
| 2006-2007 | 800 | 47 | 5,200 | 18,500 |
| 2007-2008 | 900 | 54 | 7,600 | 22,300 |
| 2008-2009 | 1,500 | 52 | 7,800 | 30,800 |
| 2009-2010 | 900 | 51 | 8,300 | 34,800 |
| 2010-2011 | 200 | 85 | 5,800 | 17,900 |
| 2011-2012 | 100 | 87 | 2,800 | 11,300 |
| 2012-2013 | 500 | 89 | 8,800 | 26,400 |
| 2013-2014 | 200 | 117 | 4,600 | 11,600 |
| 2014-2015 | n/a | 127 | 1,500 | 6,900 |
| 2015-2016 | 100 | 116 | 600 | 5,500 |
| 2016-2017 | 400 | 62 | 2,500 | 13,800 |
| 2017-2018 | 300 | 92 | 5,200 | 17,400 |
| 2018-2019 | 600 | 84 | 9,000 | 29,100 |
| 2019-2020 | 400 | 64 | 3,700 | 16,000 |
| 2020-2021 | 300 | 99 | 4,600 | 14,400 |
| 2021-2022 | 100 | 88 | 2,100 | 9,400 |
| 2022-2023 | n/a | 141 | 1,600 | 3,700 |
| 2023-2024 | 200 | 98 | 3,200 | 7,500 |
| 2024-2025 | 200 | 85 | 2,500 | 8,700 |
IVThat 2015 winter
Delaware accounted for 100 brant out of the flyway's 111,434 that January
The 2015 report from the Atlantic Flyway Midwinter Waterfowl Survey lists state brant counts from a single January. New York recorded 51,000 and New Jersey recorded 43,115. Together they accounted for most of the 111,434 counted across the flyway. Virginia recorded 11,995. Delaware's tally of 100 was the lowest among states with brant recorded in the table.
This snapshot covers a single winter and locates the brant counted during that January. Delaware's 100 covers the whole state, while the aerial figures average individual zone rows. They measure different things.
Swipe table to see every column
| State | Brant counted |
|---|---|
| Atlantic Flyway total | 111,434 |
| New York | 51,000 |
| New Jersey | 43,115 |
| Virginia | 11,995 |
| Rhode Island | 2,251 |
| Massachusetts | 1,415 |
| Maryland | 930 |
| Connecticut | 628 |
| Delaware | 100 |
VReading limits
Aerial tallies count visible birds and harvest figures come from surveys
Aerial counts record the birds observers see from the aircraft that day. What they see changes with ice, weather and survey timing. The Delaware figures do not give a flyway total. All but the final five-year block contain five January surveys, so an icy January can shift a block's average. Blocks follow calendar years and place each January flight in its own year's block. The month-by-month era comparisons draw on different numbers of survey years, ranging from 11 to 17 for each month.
Harvest estimates start with the birds hunters say they shot and expand those reports through the survey. They provide no measure of how many brant exist. A single January underlies the 2015 tally, so it cannot establish a trend. These data do not tell us what caused any of the changes.
VISetting expectations
Use Delaware's January brant counts from the post-2010 blocks
Our reading places the decline in Delaware's January brant counts between the block covering 2000 to 2004 and the one covering 2010 to 2014. Grouping five years together cannot identify the year of the change. To set expectations from the survey, use the completed post-2010 block averages of 44 to 50 birds for each zone row rather than the levels during 1975 to 1979 or during 2000 to 2004 that were near 200. An individual scouting trip should not be expected to match these survey averages.
We treat the harvest table as an approximate record and do not compare individual seasons against each other. Later-era Canada counts reach their high in January with 3,284 for each zone row. For later-era snow geese, December has the highest counts and its averages vary sharply between five-year blocks. The flyway's 2015 survey placed most of that winter's brant in New Jersey and New York.
NOTES AND SOURCES
- Source: Delaware Division of Fish and Wildlife aerial waterfowl survey, Delaware Open Data.
- Also: U.S. Fish and Wildlife Service, Migratory Bird Hunting Activity and Harvest reports (Harvest Information Program).
- Also: Atlantic Flyway Midwinter Waterfowl Survey 2015 report.
- Scope: Delaware aerial survey zone rows for October through January in two eras, 1974 to 1989 and 2010 to 2026. USFWS brant harvest estimates for Delaware 1999-2000 through 2024-2025. the 2015 Atlantic Flyway midwinter brant count by state.
- Cleaning and exclusions: Survey rows with no zone held out. Months other than October through January are not used. Delaware brant harvest is missing for 2014-2015 and 2022-2023 in the reports.
- Method: Mean birds counted per zone row (DERIVED). A zone row is one survey zone on one flight. It is birds seen, not a population estimate. Brant harvest figures are USFWS survey estimates rounded to the nearest 100 in the reports.
Fully Drawn Research is an independent data analysis desk, not affiliated with any state wildlife agency, transportation agency, mapping provider or outfitter. Fully Drawn Research is an independent data and analysis desk. This paper reports FDR's analysis of public data. Harvest figures describe animals reported or estimated as harvested, not population size, and reflect hunter effort and regulations as well as animal numbers.
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