Posted by: mynaturaldiary | October 1, 2019

Trends for birds in Teesmouth (technical!)

In an earlier post I introduced the idea of doing time series analysis. The basic techniques are explained here.

Let’s apply these methods to the data collected locally across Teesmouth to check the trends in bird populations since 2009 in a monthly measure made mid month. These are listed below alphabetically.

For each bird by clicking the highlighted text you will see the EWMA trend, the monthly data and the yearly (moving 12 mth) total. The EWMA shows each month’s value together with a 12 mth moving average. The monthly trends show the number of birds counted per month (the dotted lines indicate the envelope of the maximum and minimum values, together with the average value in between). The 12mth total plots the sum of the birds seen in the last 12mths, and is useful for determining trends in a resident bird.

Avocet

EWMA and monthly trends are shown. Note the June peak for this summer visitor. The EWMA suggests the population is slowly growing.

Cormorants

EWMA, monthly and yearly trends are shown. The EWMA suggests the population is  stable. There is an increase from July to October.

Curlew

EWMA, monthly and yearly trends are shown. The EWMA suggests the population is slowly declining after a peak in 2013-2104. There is an increase in the winter, peaking in February.

Gadwall

EWMA, monthly and yearly trends are shown. The EWMA suggests the population is slowly growing. There is a peak in numbers from August to October.

Golden Plover

EWMA, and monthly trends are shown. The EWMA suggests the population is static, with the dip in numbers in 2017 recovered in 2018. There is a peak in numbers November and December.

Great Crested Grebe

EWMA, monthly and yearly trends are shown. The EWMA  and yearly data suggests the population has decreased. There is a spring peak, between March and April.

Greylag Goose

EWMA, monthly and yearly trends are shown. The EWMA suggests the population is currently stable, having increased from 2009. There is an increase in the autumn migration, peaking in October.

Lapwing

EWMA, monthly and yearly trends are shown. The EWMA  and yearly data suggests the population dropped recently in 2017, but recovered in 2018. There is a winter peak, between November to January.

Little Grebe

EWMA, monthly and yearly trends are shown. The EWMA  and yearly data suggests the population is slightly increasing. There is a summer peak, between August to October.

Mallard

EWMA, monthly and yearly trends are shown. The EWMA  and yearly data suggests the population has declined slightly from 2009. There is a summer peak in August.

Mute Swan

EWMA, monthly and yearly trends are shown. The EWMA  and yearly data suggests the population is slowly declining. There is a summer peak, between June to September.

Redshank

EWMA, monthly and yearly trends are shown. The EWMA suggests a peak in the population mid 2009 -2010, then a decline, followed by a stable population. There is an annual peak August to December.

Shelduck

EWMA, monthly and yearly trends are shown. The EWMA suggests the population slightly declined since 2009. There is an annual peak January and February.

Teal

EWMA, monthly and yearly trends are shown. The EWMA suggests the population is stable. There is an increase from September to December.

Wigeon

EWMA, monthly and yearly trends are shown. The EWMA and yearly trends suggests the population is growing. There is a winter peak in January and February.

 

 

 

 

 

 


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