THE CHANGING SEASONS: OSCILLATIONS 
TEMPERATURE DEPARTURES FROM NORMAL 
X 
7.5 
6.5 
5.5 
4.5 
3.5 
IJE32I.I 
— 1.5 
— 0.5 
— .0,5 
”- 1.5 
r-^-2.5 
-4.5 
-5.5 
U,5 
Figure 1 . Although the spring of 2009 in Canada was just 0.4° C cooler than average on the national level, northern Manitoba was 
nearly 3° C cooler than usual, and much of northern/eastern Canada, especially the Arctic, remained locked in snow and ice well into 
June. Many species of birds delayed nesting or apparently failed to breed altogether. Map courtesy of and © Environment Canada/ 
Environnement Canada. 
Spring (Mar^ Apr^ May) 2009 
Hawaii, Hilo recorded its coolest March ever, 
and Lihue had its lowest average maximum 
temperature ever for March. From mid-April 
through late May, notes Peter Donaldson, 
“low-pressure areas and cold fronts continued 
to affect the islands [...] Rainfall distribution 
was very unusual, with some normally wet lo- 
cations setting records for dryness, while nor- 
mally dry locations had unusually wet weath- 
er” — a pattern more typical of winter months. 
Part of the driving force for these unusual 
fluctuations, especially in the West, could be 
the transition from La Nina into El Nino con- 
ditions. In March 2009, La Nina conditions 
were present but weak in the tropical Pacific 
Ocean, and although El Nino/Southern Oscil- 
lation conditions were neutral during April 
and May, rising surface seawater temperatures 
in the tropical Pacific suggested that El Nino 
conditions would be felt in North America be- 
ginning in the summer. Such conditions usu- 
ally bode well for those who dislike Atlantic 
hurricanes, which do not fare well with the 
wind shear set up during periods of strong El 
Nino conditions. 
Southern Canadian weather in spring 2009 
was similar to the adjacent northern-tier U.S. 
states. In the Maritime provinces, March was 
cooler and April and May warmer than aver- 
age; precipitation was above average for the 
first eight weeks of the period but below av- 
erage in May. Weather values were near nor- 
mal in Quebec, cooler and wetter in the 
north, warmer and drier in the south. Alan 
Wormington, writing the report for Ontario, 
characterized the season as “cold (and late) 
just about everywhere — especially in the 
north.” The province enjoyed the same warm- 
ups as the southern Great Lakes states in ear- 
ly March and late April, with similar bounties 
of early migrants in both cases. 
In many areas of northern and central 
Canada (Figure 1), March remained solidly 
locked in a winter pattern, April had perhaps 
only a single, scant warm spell, and May con- 
tinued cold and snowy, with some areas re- 
maining in winter’s grip well into June. In 
Northwest Territories, “spring came late to 
the Norman Wells and Mackenzie Valley areas 
but then erupted quickly. A rapid green-up 
gave way to subsequent cool and wet condi- 
tions,” writes Cameron Eckert in the North- 
ern Canada and Greenland region. “It re- 
mained essentially winter through May” in 
northern areas, according to Rudolf Koes and 
Peter Taylor in the Prairie Provinces region. 
and “by the end of May, many shorebirds, fly- 
catchers, vireos, and warblers were still in 
short supply in breeding areas.” May temper- 
atures in northern Manitoba were almost 4° C 
below the long-term average. According to 
Environment Canada, the spring of 2009 was 
record late in the entire eastern American Arc- 
tic. Six-foot snowdrifts blocked Churchill- 
area roads in May, and as of 1 1 June, there was 
still almost complete snow cover from James 
Bay northward, with more a meter of snow 
blanketing 90 per cent of northern Manitoba. 
“I have lived in Churchill since the 1950s, 
and this the latest spring 1 have ever seen 
here,” said Pat Penwarden, local innkeeper 
who has hosted tens of thousands of birders 
over the years. “The spring of 1962 was al- 
most this bad” (Alison 2009). A late spring in 
northern Manitoba in 1983 resulted in a sum- 
mer with almost no recorded breeding or suc- 
cessful breeding in many bird species, partic- 
ularly waterfowl and shorebirds, and that 
spring was not nearly as late as 2009. 
The Hudson Bay area has had more fre- 
quent late springs than normal: 1997, 2000, 
2002, and 2004. According to National 
Oceanic and Atmospheric Administration sci- 
entists, the Arctic is indeed warming, but 
more frequent annual oscillations in tempera- 
ture are likely to occur, often resulting in late 
springs: “such major oscillations are part of a 
bumpy ride toward global warming,” accord- 
ing to Thomas Karl of the National Climate 
Center. “For a while, at least, this vnll be the 
shape of things to come” (Alison 2009). 
We read much about El Nino/Southern Os- 
cillation in this journal and in other literature 
on bird distribution. But what of that “other” 
oscillation, the North Atlantic Oscillation 
(NAO)? We read rather little about the NAO 
on this side of the Atlantic, and even less in the 
literature on birds. Europeans, however, are 
rather well versed in the NAO and its apparent 
effects. Wikipedia (<www.wikipedia.com>) 
supplies the following definition; “The North 
Atlantic Oscillation is a climatic phenomenon 
in the North Atlantic Ocean of fluctuations in 
the difference of atmospheric pressure at sea 
level between the Icelandic Low and the 
Azores High. Through east-west oscillation 
motions of the Icelandic Low and the Azores 
High, it controls the strength and direction of 
westerly winds and storm tracks across the 
North Atlantic. It is highly correlated with the 
Arctic oscillation, as it is a part of it. Unlike the 
El Nino phenomenon in the Pacific Ocean, the 
NAO is a largely atmospheric mode. It is one of 
the most important manifestations of climate 
fluctuations in the North Atlantic and sur- 
372 
NORTH AMERICAN BIRDS 
