The 116th CBC in Alabama and Mississippi

This past Christmas Bird Count season was so dramatically unusual in the Mississippi and Alabama region that we are altering our usual presentation format and devoting a healthy percentage of our allotted space to discussing it. Throughout the region an astoundingly large number of species were reported in unusual numbers. Substantial variations in year-to-year bird population numbers are the expected norm on CBCs, however, considered in toto, this year’s data strike us as being well outside the range of normal variability. To discuss this, we present species comparisons of this year’s regional bird totals with those for the last ten years. Over that time period the number of counts in the region has remained relatively constant (29 this season vs. a range of 25-29 counts for the 10-year period), and the total number of party hours spent birding in the field on all the counts this season (1377 hours) is about 95% of the 10-year average. Therefore, we believe the reported bird numbers reflect real changes in regional population totals. Also this consistency of effort allows us to use the (number of birds reported) value for comparison between years rather than the somewhat more scientific but less intuitive (number of birds reported per party hour) as our comparison metric. 

What appears to be the obvious smoking gun for the bird population changes is the dramatically unusual weather throughout the country in the months leading up to the count period. However, we are concerned about overstating our case and want to make it clear that we are not claiming to have proved a cause-and-effect relationship between the bird numbers and the weather in a scientifically rigorous manner. We are well aware that there are a whole host of complex, interrelated, and largely unknown factors that contribute to changes in the sizes of bird populations. Not unexpectedly, some of this year’s anomalous bird data do not appear to fit our hypothesis explanation. In addition, we also do not want to give the impression that, from these bird data alone, we are making any long-term predictions about future bird population trends, or that we are suggesting that these data represent massive bird die-offs. We look forward to reading the upcoming CBC regional reports from around the country with the assumption that they will report having found some of “our” missing birds, and to a lesser extent, that we will have found some of “theirs.”

Again 2015 was an El Niño year, which became strong late in the year. Strong El Niños frequently (but not always) produce wetter and warmer than average conditions in Alabama and Mississippi. Strong rains in late October from the remnants of Hurricane Patricia (strongest ever Category 5 hurricane in the eastern pacific) broke the drought that had gripped the region earlier. Fall (October-December) rainfall totals were at record or near record levels for both the entire US and for the Alabama-Mississippi region. However, most counts reported no rain on count day, and only three reported heavy rains. The heavy fall rains throughout the central US did cause unseasonal early flooding on the Mississippi River which limited access to parts of some count territories along the river. Fall temperatures also were at maximum-on-record or near maximum levels for the entire US and for the 2-state region. A few counts started their count day with freezing temperatures, but most had very unseasonably warm weather with two counts having mid-day highs that climbed into the low 80’s. Much of this climate information was obtained from:  http://www.ncdc.noaa.gov/.

The hypothesis suggested by the bird data is that the unseasonably warm fall temperatures throughout the US acted to delay fall migration. This was particularly significant for water birds, especially ducks and geese, where northern lakes that remained ice-free through the count period allowed birds to remain north of our region. It also allowed some water birds that summer in our region to linger here, at least through the count season. Migrant land birds were not nearly as strongly affected, and there was little strongly discernable impact on resident species.

In this portion of the report, we are limiting our discussion to “common” species, which we arbitrarily define by using CBC data as those species which, for the last ten years, have been found on at least four counts each year and in region-wide numbers of at least 30 birds each year.  A total of 119 species satisfy these criteria. Random fluctuations in yearly bird numbers would indicate that in any given year, approximately 10% (~12 species) would be reported in the highest numbers of the 10-year span, ~10% would be ranked in second place, etc. However, for this count season, nearly a quarter of these “common” species (28 species, or 24%) were reported in the lowest numbers of the decade, with nearly half (57 species, 48%) being ranked in 8^th, 9^th, or 10^th place. At the high end of the distribution, only 19 common species (16%) ranked in 1^st, 2^nd, or 3^rd place.

The most heavily affected bird group was the family Anatidae (the ducks and geese), and within this group, the greatest decline in absolute numbers came from the Snow Geese. Total numbers for the region were the lowest of the last ten years, at 31% of average numbers. Typically, multiple CBCs within the Mississippi Delta (the Mississippi flood plain lowlands between Vicksburg in the south and Memphis in the north and west of Interstate 55 westward across the state to the Mississippi River) will record Snow Geese numbers that approach or exceed 100,000, with smaller numbers from counts elsewhere in the 2-state area. This year, only the region’s two most northwestern counts, Arkabutla Lake, MS and Moon Lake, MS had Snow Geese totals over 25,000. For comparison two years ago Sidon, MS’s Snow Geese numbers topped a half million, an all-time high record for CBCs everywhere.

Many of our widespread common to abundant wintering duck species that nest further north occurred on the CBC in significantly reduced numbers. Wood Duck, Gadwall, American Wigeon, Mallard, Green-winged Teal, Canvasback, and Hooded Merganser were all recorded at 10-year low levels. American Black Duck, Mottled Duck, Greater Scaup, and Ruddy Duck, all had a 10-year rank of 8^th or 9^th place. Most of these species had numbers that were less than 50% of their 10-year average, though, since they are common species, were still found on nearly as many counts as usual.

In contrast, over the last half century or so, Canada Goose has become a common resident species. This count season this species was reported in the highest numbers of the last ten years, at about 120% of its average value. Less easy to explain are Greater White-fronted Goose, and Blue-winged Teal, both winter migrants. The former’s CBC numbers ranked 2^nd at 142% of average, and the latter was in 3^rd place at 161% of average. Other common migrant ducks, such as Northern Shoveler, Northern Pintail, and Redhead, occurred in near average numbers.

Several other common migrant or partial migrant water bird species were at one or the other extreme of their 10-year ranks. Common Loon and Pied-billed Grebe (plus less common Snowy Egret, Little Blue Heron, and Black-crowned Night-Heron) all were at 10-year highs, suggesting that most winters they push further south. In contrast, American White Pelican, Great Blue Heron, and American Coot had 10-year low totals, suggesting that the bulk of their populations remained further north. Most of the shorebirds did not have extreme numbers, but some of the Gulls and Terns did. Laughing Gull and Forster’s Tern had 10-year highs, while Bonaparte’s Gull was at its 10-year low.

For the land birds, there were only a few strongly evident patterns. All the common doves (Rock Pigeon, Eurasian Collared-Dove, and Mourning Dove) (plus the less common Common Ground-Dove and White-winged Dove) all ranked in 8^th - 10^th places. However, these species are largely non-migratory and are being impacted by other factors. In particular, Eurasian Collared-Dove, an introduced species first reported in the region in the early 1990’s as its range expanded across the country from Florida, had its regional numbers peak in the early 2000’s and has been on a consistent decline since. Several of the common migrant sparrows had numbers at or near the bottom of their 10-year list. These included Field Sparrow, Vesper Sparrow, Savannah Sparrow, Song Sparrow, Swamp Sparrow, White-throated Sparrow, and White-crowned Sparrow. A few of the mega-abundant species commonly lumped together as blackbirds (with a small “b”) had low numbers, including European Starling (10^th), and Common Grackle (8^th), while others: Red-winged Blackbird, Rusty Blackbird, Brewer’s Blackbird, and Brown-headed Cowbird were all reported in average numbers.

We now continue with an abbreviated version of the regional highlights in a traditional format.  There were the same 29 counts in the two-state region this year as last, with 19 in Mississippi and 10 in Alabama. The total is only one fewer than the maximum number of counts ever for the two-state region. Together these counts recorded a total of 207 species, which is three more than last year. However, species totals for the last three years are all below average totals for the last 10 years. Alabama reported 193 species, and 183 were found in Mississippi. This year no single count reached the 150 species total. The highest was Southern Hancock County, MS at 147. The next three highest were the other three coastal counts; Jackson County, MS at 142, Gulf Shores, AL at 132, and Dauphin Island, AL at 127.  Eufaula N.W.R., AL (123) again had the highest total for an inland count. In all, only nine counts recorded species totals in triple digits, which is well below the norm, as usually about half do.

Not only did counts generally record low numbers of species, total numbers of birds were also way down. All of the counts combined found approximately 620,000 birds, which is over 100,000 lower than last year, and last year’s total number of birds was the smallest in the last 15 years. Of this total, Mississippi had about 330,000 (100,000 less than last year) and Alabama about 290,000 (a slight increase from last year). The size of these numbers each year is largely dependent on the sizes of the Snow Geese and the blackbird flocks which normally move south to winter in the region. This year the low numbers are largely the result of the absence of Snow Geese. No counts recorded over 100,000 birds, with only Gulf Shores (at 70,000), Wheeler N.W.R., AL (at 61,000), and Jackson, MS (at 57,000) breaking 50,000 birds.  Blackbirds accounted for most of those sightings.

Montgomery, AL reported the only Tundra Swan.  Northern Bobwhite continued their long-term downward trend with a total of 23 reported from three counts (max 15 at Noxubee N.W.R.). A Pacific Loon was reported at Gulf Shores.  A total of 1006 Common Loons were found on eight counts, with a max of 648 at Guntersville, AL. Guntersville also reported the only Red-throated Loon.

Anhinga numbers rose dramatically in the south Mississippi Delta in the three winters prior to the major flooding of the Mississippi in the spring of 2011 (max 52 at Eagle Lake on 22 Dec 2008). However, following the flood, combined numbers for the four counts in the south delta have remained fairly steady at single digit values (e.g., 7 at Eagle Lake and 1 at Vicksburg this year). However, in the past few years, small numbers have started to be more commonly reported at non-traditional locations within the interior of the 2-state region (e.g. 6 at Eufaula this year). At the same time, along the coast numbers have remained fairly steady in the low double digits (14 at Southern Hancock County and 1 at Jackson County this year).

Dauphin Island reported a Great Shearwater, a count week Masked Booby, and 135 Northern Gannets, all good finds. Gulf Shores had an additional 33 Northern Gannets. Thirteen Wood Storks, rare in winter, were found in Natchez. Eufaula and Gulf Shores each had an American Bittern. Dauphin Island had the only Green Heron, while Southern Hancock County had the only two Yellow-crowned Night Herons. Jackson County had a count week Roseate Spoonbill. Most of these wading birds are more common in summer and likely lingered into count season due to the warm weather.

Bald Eagles (region total of 249 this year) continue to show a strong recovery from the effects of widespread DDT use in the 1950’s and 60’s. There were six years in a row in the mid to late 1960’s when there were no Bald Eagles reported on any CBC in Mississippi or Alabama. However, following that period they started a long slow recovery that has gradually picked up speed. They are now routinely reported on 70-80% of the counts in the region, and this year’s total is 50 birds higher than were reported just three years ago.

A Golden Eagle was a good find on the Jackson County count. Whooping Cranes have been reported at Wheeler N.W.R. every year for the last nine years, following reintroduction efforts. Numbers had climbed into the teens for the three most recent prior counts. However, this CBC season, only three were reported. A total of 1470 Wilson’s Snipe were reported on 18 counts, with Dahomey-Great River Road reporting 1183 of them, the highest on any count in the country this year. Sixteen American Woodcocks (max 9 on Jackson County) were reported on six counts with two additional counts having count week birds. Dauphin Island and Sardis Lake both reported single Lesser Black-backed Gulls. Natchez has reported Inca Doves on each of the last ten CBCs, with ten this year. The only Short-eared Owls this year were two at Arkabutla Lake. Wintering hummingbirds, mostly along the coast, are slowly approaching their former pre-Hurricane Katrina levels. This year Gulf Shores had an impressive three Ruby-throated, two Ruby-throated/Black-chinned, two Rufous, four Selasphorus sp., and a Buff-bellied.  Birmingham and Montgomery also each reported a Rufous. Hattiesburg had a Calliope, and Jackson County had a count week Black-chinned.

One of the best birds this season was a Say’s Phoebe, found on the Sidon count. Other good flycatchers included two Vermilion Flycatchers on the Jackson County count, with another on the Southern Hancock County count, and a Western Kingbird unusually far north at Tuscaloosa. Uncommon Warblers put in a respectable showing with single Black-and-white Warblers at Eufaula, Lauderdale County, and Southern Hancock County. Eufaula also had a Nashville Warbler and Dauphin Island had a Northern Parula. Le Conte’s Sparrows were found in greater than normal numbers, with seven at Sardis Lake, five at Grenada, and singles at Auburn, Arkabutla Lake, and Natchez. Gulf Shores and Waterloo each had a Summer Tanager. Finally, Baltimore Orioles were present in above average numbers, with three at Eufaula, two at Auburn, and singles at Gulf Shores and Montgomery.

Thanks to the 466 of you who spent those 1377 hours traveling 7021 miles (by foot, car, boat, and golf cart) counting birds in the field plus the additional 19 of you watching feeders. A special yawn of thanks to those of you who spent those 43 pre-dawn hours owling. See you next year. Bring your friends!