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Kororā Data Analysis Report

Comprehensive analysis of Little Penguin conservation databases tracking individual birds, nests, and resightings across New Zealand beaches

Executive Summary

We have three interconnected databases tracking Little Penguin (Kororā) conservation efforts in Taranaki. These databases monitor individual birds, their nests, and resightings across two beach locations: Urenui Beach and Wai iti Beach.

Key Numbers at a Glance:

78

individual penguins

registered and tracked

42

nests

monitored across both sites

869

nest checks

conducted over 2+ years

18

resightings

of tagged birds

Database 1: Kororā ID Database (Bird Registry)

What This Database Contains

This is your master registry of individual penguins. Each row represents one penguin that has been tagged and measured. Think of it as a "birth certificate" or "passport" for each bird.

Key Information

Bird Demographics

Age Distribution:

  • Adults: 75 birds (96%)
  • Chicks: 3 birds (4%)

Sex Distribution:

  • Male: 53 birds (68%)
  • Female: 21 birds (27%)
  • Unknown: 4 birds (5%)

What Gets Measured

When a penguin is registered, researchers record:

Basic ID

Bird ID number, tag type, date/time, location

Physical measurements

Weight, bill depth, bill length, foot length, head length

Demographics

Age, sex, species

Optional

Nest ID (if found at a nest), mugshot photo, name, comments

Data Completeness Issues

93.6%

Missing Nest ID

Most birds were not tagged at a nest

17%

Missing Bill Length

Some measurements not taken

85%

Missing Foot Length

Rarely measured

100%

Missing Head Length

Almost never recorded

Only 1 bird has a name — Naming is not standard practice

Database 2: Nest Checks Database (Breeding Monitoring)

What This Database Contains

This tracks nest monitoring visits over time. Each row represents one visit to a nest where researchers check on breeding activity, count eggs/chicks, and record which adult birds are present.

Key Information

Nest Status Breakdown

Attendance Patterns

When researchers visit nests, they record who's home:

Empty

367 checks (71% of recorded attendance)

Single adult

55 checks (11%)

Pair of adults

20 checks (4%)

No adults (but eggs/chicks present)

22 checks (4%)

Unknown

53 checks (10%)

Breeding Activity

Eggs:

  • Recorded in 507 checks (58% of all checks)
  • Most common: "Unknown" number (405 times) — eggs present but not counted
  • When counted: 0 eggs (76), 2 eggs (15), 1 egg (11)

Chicks:

  • Recorded in 489 checks (56% of all checks)
  • Most common: "Unknown" number (403 times) — chicks present but not counted
  • When counted: 0 chicks (67), 2 chicks (11), 1 chick (8)

Interaction Types

98%

Passive observation

849 checks — No handling

2%

Transponder scanned

19 checks — Bird ID verified

<1%

Device deployment

1 check — Equipment installed

Data Completeness Issues

  • 37% missing Observer — Not always recorded who did the check
  • 41% missing Attendance — Often not recorded if adults were present
  • 95% missing Adult IDs — Rarely identify which specific birds are present
  • 98% missing Chick measurements — Weight and head length almost never recorded

Database 3: Resighting Database (Bird Observations)

What This Database Contains

This records opportunistic sightings of tagged birds outside of formal nest checks. Each row represents one observation of a tagged bird, typically when researchers spot a bird they've previously registered.

Key Information

Bird Status at Resighting

Commuting

13 observations

Bird moving between locations

Dead

3 observations

Deceased bird found

Roosting on/near nest

2 observations

Resting at nest site

Most Frequently Resighted Birds

Three birds have been resighted 3 times each:

Bird ID:

956 0000128 25471

Bird ID:

956 0000122 24628

Bird ID:

956 0000122 39990

All other birds (9 birds) have been resighted only once.

Interaction Types

  • Passive observation: 10 resightings (56%)
  • Transponder scanned: 5 resightings (28%)
  • Band read (handled): 3 resightings (17%)

Data Completeness Issues

56%

Missing Weight

Most birds not weighed during resighting

11%

Missing Location

Specific location sometimes not recorded

78%

Missing Images

Photos not always taken

How the Databases Connect

Bird ID Coverage

  • 77 birds are registered in the ID database
  • 12 birds have been resighted (all 12 are also in the ID database)
  • 65 birds have been registered but never resighted
  • 0 birds were resighted without being in the ID database

Nest Coverage

  • 3 nests appear in both the ID database and Nest Checks database
  • 39 nests appear only in the Nest Checks database
  • 0 nests appear only in the ID database

What this means: Most birds were not tagged at their nests. The nest monitoring program tracks many nests where the adult birds have not been individually tagged yet.

Adult Birds in Nest Checks

  • 8 unique adult birds are identified in the nest checks (Adult 1 or Adult 2 columns)
  • All 8 of these birds are also in the ID database
  • This represents only 10% of registered birds (8 out of 77)

What this means: Most tagged birds have not been observed at nests, or when they are at nests, they are not identified by their individual ID.

Data Quality Summary

Strengths ✓

Good temporal coverage

Data spans 2-4 years depending on database

Consistent tagging

All birds use the same Trovan 11mm transponder

Good data integrity

All resighted birds are in the ID database

Regular monitoring

869 nest checks show consistent effort

Two-site coverage

Both Urenui and Waiiti beaches monitored

Weaknesses

High proportion of "Unknown" values

Many nest checks record "Unknown" for eggs, chicks, and status

Missing observer data

37% of nest checks don't record who did the observation

Incomplete linkage

Most birds not linked to nests (93.6% missing Nest ID)

Limited morphometric data

Foot length and head length rarely measured

Low resighting rate

Only 12 birds (16% of total) have been resighted

Minimal adult identification at nests

Only 8 birds identified at nests despite 869 checks

Recommendations for Improvement

01

Standardize nest check protocols

Reduce "Unknown" entries by always counting eggs/chicks when possible

02

Improve bird-nest linkage

Record Nest ID when tagging birds at nests

03

Increase transponder scanning

Scan adults during nest checks to identify which tagged birds are breeding

04

Standardize measurements

Decide which measurements are priority and ensure they're always taken

05

Improve observer recording

Always record who conducted each nest check

06

Increase resighting effort

Consider systematic surveys to resight more tagged birds

Timeline Overview

Data Collection Periods by Database

Glossary of Terms

Kororā: Māori name for Little Penguin (Eudyptula minor)

Transponder: Electronic tag implanted in the bird that can be scanned to read a unique ID number

Trovan 11mm: A specific brand and size of transponder tag

Resighting: Observing a previously tagged bird in the field

Nest Check: A monitoring visit to a known nest site

Attendance: Whether adult birds are present at the nest during a check

Interaction Types:

  • Passive: Observation only, no handling
  • Transponder scanned: Bird ID read electronically
  • Band read (handled): Bird caught and leg band read
  • Device deployment: Equipment (camera, logger, etc.) installed

Status:

  • Breeding: Eggs or chicks present, active breeding
  • Not breeding: Nest present but no breeding activity
  • Failed: Breeding attempt unsuccessful
  • Fledged: Chick has left the nest successfully
  • Moulting: Bird replacing feathers
  • Commuting: Bird moving between locations
  • Roosting: Bird resting at a site

Visual Summary

Five visualization charts have been created to help you understand the data:

1

Bird ID Database Overview

Shows distribution by site, sex, age, and registration timeline

2

Nest Monitoring Activity

Displays nest checks over time, status, attendance, and site distribution

3

Breeding Activity Analysis

Tracks breeding checks, egg/chick counts, and most monitored nests

4

Bird Resighting Analysis

Shows resighting timeline, status, and most frequently seen birds

5

Database Integration & Coverage

Illustrates how the three databases connect and data completeness

Questions This Data Can Answer

With these three databases, we can investigate:

1. Population questions:

  • How many penguins are in the study area?
  • What is the sex ratio?
  • Are more birds at Urenui or Waiiti Beach?

2. Breeding questions:

  • Which nests are most active?
  • What is the breeding success rate?
  • When is the breeding season (based on egg/chick observations)?
  • How many eggs/chicks per nest on average?

3. Monitoring questions:

  • How often are nests checked?
  • Which nests get the most attention?
  • Are there gaps in monitoring coverage?

4. Individual bird questions:

  • Which birds have been resighted?
  • Which birds are breeding (if identified at nests)?
  • What are the physical characteristics of the population?

5. Survival questions:

  • How many tagged birds have been found dead?
  • What is the resighting rate (proxy for survival)?

Next Steps for Analysis


Breeding season analysis

Plot egg/chick observations by month to identify breeding season timing

Nest success rates

Calculate what percentage of nests with eggs successfully fledge chicks

Survival analysis

Use resighting data to estimate survival rates

Site comparison

Compare breeding success, bird size, or other metrics between Urenui and Waiiti

Individual histories

Create timelines for specific birds showing all their observations across databases

Morphometric analysis

Analyze weight, bill measurements by sex or site

Monitoring effort

Quantify observer effort and identify gaps in coverage